Cyberrabbi

Hello everyone. Have been on here before but don't remember my log in, but you guys were very helpful a few years ago. I am 25 years old and have had my SC 300 for almost 10 years now and gone through hell and back with this thing. I'm not a "DIY" guy, as I have quite literally no spatial reasoning, manual dexterity, tools, education, or time, but regardless I do want to keep the car as long as I can as there's a lot of sentimental attachment (plus I am finally at a point in my life that I can actually afford to repair the poor thing for more than just breaking down). I'm going to divide the potential problems as well as my own thoughts, and would invite any help or comments you all are willing to provide. I appreciate your help in advance : ). Also I apologize in advance for a lot of "dumb moves" and rookie mistakes as basically I've recently decided to stop using a repair shop I've been using since I've had the car and start being my own advocate. I'm going to be honest about all this, including my mistakes, so I can hopefully learn from them. First one is the longest, I promise. Also my car is just over 200K miles now.

1) Possible cracked head gasket-- So emphasis is on -possible-. Awhile ago (about three months ago) I was visiting my mom's place and my car started overheating. I was on the highway but I had been through this before, so I was fairly careful to keep it out of the red until I could get it off onto the side of the road. I was thankfully within free towing distance (with my insurance) to the car repair place I've been going to for years. They say the lower radiator hose had ruptured (which made sense as the upper one had about four years ago and replaced, and the lower one had never been replaced). They suggested I replace the upper radiator hose as well just for safety as it was "old". I said alright, as I didn't (and still don't) know what qualifies as an old radiator hose. So the cost to replace both hoses, the thermostat and gasket and thermostat bypass hose (as well as air filter since apparently that was dirty), ended up being 734 dollars. According to https://repairpal.com/r/s/1034ed08-9...9-0c68c6482540 that was a bit over priced but it doesn't mention replacing the bypass hose, and that was 130 labor and 23.60 part, so I don't know. Regardless I chose to trust them as I had used them for awhile. Unfortunately there had been several times recently that I had brought the car in for a problem, and they fixed a problem I didn't know I had, didn't fix the previous problem, and this caused new problems. Example being after a multiple thousand dollar repair my alternator apparently was shot because, I think, they got oil all over it in the repair.

At the tail end of December I was visiting again and started overheating, which thankfully I was DEFINITELY able to pull over before a problem. The car after the repair had the heat go up SLIGHTLY when driving but not to a point where I thought I had cause for concern. Regardless, apparently the upper radiator hose (the one that didn't actually rupture but they replaced because they said I should), ruptured, but was apparently caused by the heater control valve having problems that they apparently never detected with their pressure test (not sure if it's reasonable to expect them to have found that or not, but there you go). They, without asking me or telling me about it first, did a heater control valve bypass and replaced the upper hose and charged me 317 dollars for it. Long story short I tried briefly to fight them on this but given that it was a "different part" and "wasn't their fault" I just decided to not use them again. The receipt indicated that coolant was getting into the oil and my head gasket was bad. They explicitly stated previously the headgasket was NOT cracked/bad and they said they didn't think it was because of the heat but because the engine was old (engine had been replaced by a refurbished one around four years ago, but to be fair the people that did it were crooks). The car HAS been leaking oil for quite awhile, and on the first repairs they indicated that I appear to be leaking oil from the "timing cover gasket" that is blowing backwards onto other parts, which seems possible but I haven't verified this elsewhere. Regardless they couldn't get their story straight, as the owner told me that oil was getting into the COOLANT (and just that) whereas the sheet says coolant is getting into the oil (and just in that direction). Regardless, there is no milky white residue, there's no more overheating or seeming coolant loss, there's no oil underneath the radiator cap, there's no excessive exhaust that smells like coolant, etc. If oil is getting into the coolant, as I understand it even if I do have a cracked head gasket that problem is mainly that it'd gum up the water pump and hoses (both of which is SIGNIFICANTLY cheaper than replacing a headgasket, as I am unwilling/unable to do this myself), and other than it leaking a lot of oil and has been forever (about half the dipstick every month or two) there's really no other symptom of a cracked head gasket. I think they're trying to get extra money out of me since I ASKED if it cracked, they can tell I'm attached to it, and I've paid for a LOT with this car through them. Plus I know that a cracked head gasket is almost ENTIRELY labor costs, so I'm sure that they know that. So in short, are my instincts seemingly correct? How can I verify whether something NEEDS intervention, preferably using a repair place, without necessarily giving them an excuse to say "yup head gasket" if that's not the case? Even if I do have a cracked head gasket, how important is it that I repair it IMMEDIATELY if it is not overheating at all?

2) Timing cover gasket- Assuming this is not a head gasket, and assuming this is leaking, what would this do to the car other than start eroding the timing belt? How much would this be to get fixed (since it appears to be on the FRONT of the engine and as such easier to access)?

3) Heater control valve- This I believe them that it needs to be replaced, as one of the tubes looks like pieces have fallen off due to rust or something. Given that they said that I could go to like, home depot and just get a twist valve or something, that leads me to believe that as long as I don't insist on an original part (I don't) that it'd be fairly easy to replace. According to https://www.clublexus.com/forums/per...t-numbers.html I can use the Everco 74636 heater control valve, and replace that in the assembly. Even though this sounds the SIMPLEST of the DIY is it reasonable to believe that a halfway decent repair shop could do this? Is there anything that I'm missing? Once again I am totally uneducated and suck at these sorts of things. Also would the car work the way it did with this part as it did with the original part, or do I need to flip a lever or something (it APPEARS to make it almost the exact same part again)? Also, right now my car blows hot air just fine (guessing because it goes to the heater core directly?) but won't blow cold (which is kinda necessary for Texas "winters"), so I'm assuming that if this would work that'd fix it? Is it unreasonable to get them to put this part into the assembly itself like the person did in the thread?: https://www.clublexus.com/forums/per...l-valve-5.html

4) Lower control arms/bushings- So I've had two different places verify fairly immediately that something is up with my lower control arms (which I think causes the car to shake somewhat when I get to higher speeds for awhile). I'm fairly certain the bushings got worn to hell because brake check gave me a bunk part causing the brakes to engage near constantly (luckily this has been fixed). Regardless, both verified that the lower control arms themselves aren't broken or cracked, and both agreed that replacing the bushings would probably fix the problem (only after I suggested it of course). The crooks from number 1 for some reason after I brought this solution to them AGREED but still insisted I replace the lower control arms. Apparently the "bolts are kind of worn". I asked if I couldn't just replace the bolts rather than the control arms themselves. They said no you can't just replace the bolts and not the control arms (maybe they meant ball joints?). Lexuspartsnow lists several bolts that you can BUY separately, so it makes me feel like they are yanking me around. If the "bolts are worn" is that enough that the ENTIRE control arm would need to be replaced? If so, what is the best/cheapest way to do that (apparently getting the Supra LCA's?)? If not, is it a good idea to get the bolts and get that taken care of while replacing the bushings, or would that be significantly more expensive? According to both of them I should probably replace ALL of the bushings, but no one around me provides JUST bushings so I'd need to bring the part in. If I wanted to replace all of my lower control arm bushings, what parts should I bring to them? This seems pretty overwhelming because it seems like if the balljoints are shot one should just go ahead and get the Supra LCA's, but if they aren't, then the bushings may be fine, but after driving it for so long, the ball joints are probably worn anyways? There's a lot of confusing and seemingly contradictory information. I'm seeing suggestions for Prothane or Daizen, and that some bushings cause squeaking while others are just fine.

5) Struts- So after riding with my Dad in the car for a bit, he thinks my struts/shock absorbers need to be replaced as basically the car -feels- every bump. I'm not certain if I should fix the lower control arm problems FIRST and see if that fixes it, or if it should be an "all in one" endeavor to save on labor costs. Apparently the shocks themselves aren't terribly expensive, but the labor absolutely is, so I figure saving labor costs would be a smart plan.

So I know that may be a lot of information and maybe anyone that's read this is shaking their head at how little I know. I also realize I don't have any pictures but I wouldn't even know what to look for. Regardless, the long and short of it is the health of my car takes priority over how good it feels to drive which takes priority over how it looks/keeps the "pristine OEM unmolested" parts. In that regard, the order of priority for how I spend my money goes that way as well. To give you an idea how such an ignorant college boy could justify spending so much on a car they barely understand, this was my dad's first "I bought this car because I specifically wanted this, not just because I could afford it", and he gave it to me because he trusted me to take care of it. It's been the one possession I've really cared about that I was able to keep through some really dark times. As ludicrous as it may sound, it has "never betrayed me" and even when it's had problems it has always "kept me safe." I genuinely love the thing, and I feel awful because some not nice people have taken advantage of me and -I- feel have "hurt" it with shoddy repairs, made up problems, or faulty parts. I just want "her" to feel right again, and while I don't have the capability to do it MYSELF per se, I'd still really like it to happen. I also want to at least make sure I'm not killing her by assuming something is "optional" when it really isn't. Hopefully that makes sense.

I appreciate whomever may have stayed in my thread's help if you have come this far. Please assume I am basically an idiot (as I am) in your explanations/questions and also assume that I will not be doing any DIY work.

Duck05

Wow.... In reading your story/history I can almost match you word for word. I am also not a DIYer and have had to research and select the best vendors I could find.

My first independent shop (no way do you want to use a Lexus dealership for our 1st gen SCs) was adequate to get a car going again but not that capable. Almost all of the repairs they did I had to have re-done.

I had two separate over heating events. One due to the heater control valve failing (which the first shop failed to diagnose) and the second when the cheap water pump the first shop installed failed after only 13 months. Having two over heating events did lead to a blown head gasket all of which were repaired by new vendors (I now have 2 "go to" shops I use depending on what is needed.)

As for the LCAs and struts, since I had desires to lower the car anyway that was a new investment. I had one of the new shops replace the steering rack where the LCA bushings were discovered. After having the struts replaced with coil overs, had them replace all of the bushings using a Prothane bushing kit. The old, softer bushings have to be literally burned out of the control arms and then replaced with the new, hard polyurethane with steel/zinc sleeves. The ride is stiff and "race car" like but the steering is fantastic.

All of the above represented over $3300 not including the head gasket repair. The head gasket is a turning point and many recommend to do an engine swap to a 1J but I elected to stay with the existing engine instead. A 1J is more upgradable for turbo charging and you can get some impressive horse power numbers if that is the direction you want to go. The stock engine was good enough for me as I was going more "show" then "go" with our car.

My best advice is to discover a shop or shops that has good references and one that you can trust. Not an easy task. Both of my two shops are over 50 miles away (in opposite directions, no less) and only they get to touch the car. I have AAA towing with 150 mile distance coverage.

Good luck with your research and auto shop selections.

Cyberrabbi

Thank you for your response man. Glad to know I'm not alone in that. Thankfully the headgasket I'm fairly certain isn't the issue, and if it IS it isn't going to be a major issue for quite a while. Regarding the control arms, shockingly enough I've found OEM, new, well reviewed front lower control arms for half the price that they quoted. It's maybe 80 bucks more expensive than the Supras but get to keep that original feel no less, plus compared to the quotes I've gotten for having to burn the bushings, it isn't even THAT much more expensive than the bushings themselves. According to just brief online price estimates, the labor is about 300 dollars for the front lower control arms (which I'm assuming is the problem though it isn't THAT much more for the back lower control arms apparently), so about 1000 bucks for brand new OEM front lower control arms. The shocks, which are probably shot since they've never been replaced and are 24 years old, is the expensive part as the shocks THEMSELVES are maybe 100 or so a piece, but the labor is around 800. Maybe I'll get a bulk discount deal if I get em done all at once?

Regardless I'm feeling encouraged as even if I -did- have to replace the lower control arms, I'm feeling confident I can stick with new OEM replacements and not COMPLETELY break the bank. Maybe be around 2500-3000 to fix everything I want to other than the oil leak (meh) and POSSIBLE head gasket (meh). Depending on the cost of the timing cover gasket, may do that as well. Gosh that'd be amazing. All I'd have to do at that point is fix the cosmetic things and I'd have the car back to basically when I first had it. Maybe even better.

Duck05

Your quote on labor for replacing the struts seems way out of whack. I went with really pricey Tein Street Flex coil overs (almost $1500 for all 4) and the labor was $380. Hope the shop you plan to use has a lot of experience with suspensions.

Cyberrabbi

To be fair I haven't taken it to a shop yet, just one of those online estimates. And the one I will probably take it to does, as they do a lot of restoration work for totaled cars. Also they're family of a coworker so sort of have an "in" hopefully.

KahnBB6

iTrader: (5)

Cyberrabbi,

That is a tough situation you are currently in. I've gone through most of those myself. To address your points:

1.) Cracked head gasket:

This is a tough call if no other part of the cooling system is causing your occasional overheating(cracked radiator, bad hose, bad/leaking HCV valve, etc.). To really determine whether your head gasket is leaking you can use what is called a "combustion leak tester". This is a relatively simple device that affixes to your radiator (when cold) and uses two stacked tubes filled with special solutions to detect the presence of gasses that would indicate a leak. I've earmarked a UVIEW 560000 model ($60 online) because... well... I need to test for this soon myself on my current engine. If you do a youtube search of "combustion leak tester" and view examples using two stacked tubes you will get a sense for how this works. You can do it yourself or have your mechanic do it.

If you do have a leaking head gasket it is not entirely certain how stable the current state of it will be. It varies but IF that is truly one of your issues and can be confirmed to be so then yes, you do need to address it or... swap to another engine. If it is a leak that is contaminating your oil you can monitor this by sending oil samples to Blackstone Labs (via Fedex or UPS only. The USPS has officially stopped allowing shipment of sealed engine oil samples as of about 6-8 months ago). It adds cost but is a good way to monitor things.

Depending on how severe this might be you can change the oil very frequently (like 500-700 mile intervals) to keep bearing wear down (temporarily).

But again... that's a variation on a compromised head gasket you should have confirmed. Generally when a head gasket really does completely let go it is VERY obvious and not really possible to use the engine any longer until it is repaired.

I feel you should have some things confirmed first before calling this one. But it is good to play it safe too. I hope this is not actually the case for you. I would address your HCV assembly if leaks there can be confirmed. But also if you have suspicions running that combustion testing kit is a good way to check your head gasket health before spending a lot of money to find out.


2.) Timing cover gasket:

This I have never personally addressed. To my knowledge it should not immediately affect any part of your cooling system. I don't believe I am incorrect on this but someone please correct this statement if I am. That gasket should just be to seal the timing belt area from dirt and debris.

3.) Heater control valve:

This can cause phantom overheat symptoms when it leaks. I have personally experienced this. Yes, you can buy an Everco 74636 HCV valve, remove your old HCV (and get some new OEM hoses and OEM clamps or aftermarket screw clamps if possible) and perform the swap as described in the thread: https://www.clublexus.com/forums/per...ml#post8587609

Another CL member found that model valve among several others a while back and I tried all of them. The Everco/Four Seasons 74636 is a near identical match for the valve in our HCV assembly but it does require some careful Dremel trimming on one side to clear the mounting area. And the original arm from your old plastic valve is required to swap over. It does work, yes. I feel an OEM assembly will be the best quality but for only $40 or so it's infinitely cheaper for a part the works exactly the same way and is 99% the same shape and functional operation.

It's just that Toyota/Lexus sells an entire assembly and not just that little plastic valve that tends to break after 20+ years.

Handing the procedure over to a shop... I think would depend on the shop/mechanic and how well they can work from a DIY instruction set that will not be detailed in their AllData machines that show them all the original TSRM procedures from Toyota/Lexus. Personally I'd recommend you do it yourself with your own Dremel unless you have a very good mechanic who is willing to do a few things outside of the box.

In the short term you can connect the two hoses the valve is meant to bypass to the heater core behind the dash (and cap off your heater core hoses temporarily) and the car will operate normally, just with no heater function.

The leaking HCV area caused me several headaches until I got in there and repaired it.

For reference the OEM Heater Control Valve assembly is Toyota/Lexus P/N:87240-24040


4.) Lower control arm bushings (usually the front lower):

Common to go out on these cars after 20+ years or 180k+ miles. Well... these model are all old now so it's common to see. The car will seem to "shimmy" or "waddle" a bit at speed.

There are more expensive options but your best bang for the buck is to replace with Supra MKIV front LCA's as you discovered:

1993-1996 Supra MKIV NA/TT Front LCA Left -- 48069-14080
1993-1996 Supra MKIV NA/TT Front LCA Right -- 48068-14080

Also, this is a good time to address the other cause of the shimmy and shake: your steering rack bushings. Order a set from Daizen (Amazon has them listed as well) and have those installed. Should be Daizen P/N S1-2030 for 1992-2000 SC300's and SC400's.

5.) Shocks:

Again, not uncommon to see these having become worn after 20+ years if they are original. I would address your lower front control arms and steering rack bushings first before doing the shocks unless they are severely blown. You could replace them with OEM shocks but it would also be a good time to upgrade to a reasonable suspension setup that offers a more complaint and sporty ride (without being a full track suspension).

On the stock springs (very soft) I believe KYB and Koni make OEM replacements but there are also off the shelf coil over suspension kits and other options to choose from. Generally any coilover/spring/shock made for the Supra MKIV 93-98 will also fit the SC300. It is really up to you how you wish to address this as there are so many suspension options for these cars.

Additionally I will suggest that after your initial issues have been addressed, swapping in 1995-2000 Lexus LS400 front brake calipers is an excellent night and day upgrade for both performance braking ability and general safety with a spiritedly driven sports GT car.

Cyberrabbi

Dear Kahn,

Thank you for the detailed reply! I'm sure that a decent mechanic could test the coolant/oil for a cracked headgasket, but regardless, I'm pretty sure they were making it up as there is absolutely no signs of it otherwise. You are right though that it is better safe than sorry. I don't have a dremel personally and I'd definitely trust a professional far more than myself if they're willing to work that, though I guess worst case scenario I ruin a 40 dollar part, good to know regardless.

Also, dumb question, it's 87240-24040? Not 55902-24010? Because that makes so much more sense. They said it'd be like 900 dollars for the part alone, and thus when I looked up "heater control valve" on lexuspartsnow, I assumed it was the far more expensive one. Like god dang I can get one from Ebay for like 90 bucks, or in the very least from lexuspartsnow for 180. Like I'm not crazy right? Even brand new ones on there are 500. Talk about scam artists. Regardless as you said it's infinitely cheaper to just modify the other part and get it fit in. Luckily I have some time until I -really- need AC. Actually would prefer no heater over not having AC.

I am 99% certain my steering rack bushings have actually been replaced this past year so thankfully that's not an issue. Definitely would be around that time though! Also strangely enough there's a set of both front lower control arms for 700 dollars, factory new, OEM and everything, for around 700 bucks. Frankly given that the ball joints are likely worn/going to be worn soon I'm tempted to just get those and start fresh. Hell it's only a little more expensive than the Supra anyways.

If I may ask, what suspension set up would you recommend? Assume I know literally nothing (as this is in fact the case) and am a recently graduated graduate student with their first kind of sort of "real job" that pays a decent wage. If you don't feel like going into that I fully understand and appreciate all the help you've given already!