oaksc400

I have searched every post relating to overheating.. within 15mins after warming up, the temp. Needle slowly makes it way to the top. My heater does not blow hot air either. It's not a bad radiator cap nor do I have any visible leaks..the overflow tank is full with coolant also. the radiator hose gets hot really quick and feels like there's no water going into the engine block. Could it be a bad water pump? Also my radiator was replaced 2 yrs ago.. I just did a full tune up (wires,plugs, caps) now this happens.I'm PRAYING it isn't the head gasket but I'm at a lost. Any advice CL?

-Andy

ArkLaTexSC

Well, something's clogged, clearly. You haven't had any forays with aftermarket Leak Sealing-type, have you?

eknine9

iTrader: (8)

When's the last time your engine thermostat was replaced?
When mine went bad it was stuck closed and there was pretty much no circulation of my engine coolant, causing the cars engine temp to just slowly creep up until it had to be turned off while I waited for the temp to go back down. It's worth checking out, and it's an extremely cheap replacement part. I doubt I paid more than $35 at the time, and I did a full coolant drain and fill with toyota red/water at the same time.

SC400slide

iTrader: (11)

^Like eknine mentioned, Thermostat might be stuck closed. Does happen a lot to these cars, in fact, the thermo on my 95 is stuck open.

oaksc400

I forgot to mention changing the thermostat was the first thing I did. I bought a aftermarket one for 20 bucks. I'm gonna have to take it down to the local shop down the street and keep you guys updated. Wish me luck

Dawa

iTrader: (5)

thermostat would be my first guess. before you replaced the thermostat with an aftermarket one, did you test it to ensure that it works and is not defective? also, did you test the old one to ensure it was broken before you threw it away?

oaksc400

It didn't look like the problem was the T.stat. I changed it out anyways so I called the shops today the lolowest price I could find was $780 (water pump&timing belt+labor) some guy even wanted 950!!! What I'm trying to ask is if I can DIY the water pump and & timing belt and save big? Also I'm wondering if there is anyway to check if the radiator is clogged? There goes a pay check :'( :'(

eknine9

iTrader: (8)

That's not so bad for the water pump and timing belt. Problem is there's a lot of other stuff in there you'll want to replace since you're that far into the motor so not doing the other stuff is kind of a waste.
You can do it yourself, but it's a lot of work, and if you don't have a lot of experience in there expect to work a full weekend getting everything off.

Don't know how to test if the radiator is clogged. I just shoved my garden hose into the upper inlet for the top radiator hose and turned the hose on full, a bunch of gunk came out of the bottom and I let it run until clear water was coming out of the bottom. Then I re-connected everything and filled it up with Toyota Red/water. But I did this at the same time I did my Thermostat. It's definitely worth a shot before you jump into the much more expensive water pump and timing belt repair.

pcolex

I had the same problem with my 93. I did all the normal routines like flushing the coolant system, checking and replacing the thermostat, and all failed to fix the overheating. The only thing left was the water pump. It turned out the impeller had broken free of the shaft so coolant was obviously not flowing anywhere. I replaced it, and since I was in there so deep I also replaced the cam/crank seals, pulleys, timing belt, drive belt (there are good kits), and also distributors/rotors and a failed coolant reservoir sensor.

oaksc400

Haven't had the time to get the car looked at. I've been calling some craigslist "mechanics" and explaining them my situation.. one particular mechanic(claims to be ASE certified) got my attention.. we talked on the phone for about half-hour. He was going on explaining he has never seen a "broken" water pump on a Lexus since they are made of steel impeller? Unlike some plastic counterparts. Anyways do you think I should pay him a $85 diagnostic fee? Or not go with craigslist mechanics at all.

-Andy

pcolex

My water pump was absolutely broken. The impeller broke free from the shaft. The impeller was plastic. My 93 SC4 has 180K miles on it (175K when I bought it). I had no history from the PO on the age of this water pump. But based on the condition of the timing belt it was fairly recent in SC4 years - within the last few years. Makes me think it wasn't the best pump. Keep in mind you may also have a replacement pump that has similarly failed. If you are going to replace yourself, don't pay for the diag - just get parts and dig in. However, if you are getting this guy to do the work, make him waive the diag fee and just bid on the work for the pump, belt, pulleys and cam/crank seals.

salimshah

Somethings are easy to test.

With the engine cold, open the radiator cap. run the engine and see. As the engine gets warm you should see circulation. If you dont, then either the pump is out or your thermostat is stuck closed.

When pump and thermostat are working then temp of the block will almost match the radiator top temp.

Thermostat is 2 bolts, 1 gasket and 2 cups of coolant and simple/easy as can be. To eliminate, you can remove the tstat and go direct [will be bad for fuel economy but can be done to test out].

The mechanic you found is wrong about the pump. The impeller is plastic. Just recently I found out that the SC pumps are not as robust as the ones used in RX. I got mine from ToyoLex.

Salim

Ali SC3

iTrader: (10)

how old is the pump or how many miles.. I mean if its got like 200k on it then yeah change the pump. t-stat you should have changed right away like you did. you said timing belt and pump so that makes me think its an old pum anyways. some badly advised people will also do the belt without the pump which is terrible and you could be going on a potentially third one with the original pump, which is a disaster waiting to happen.

if you have a flashlight just go out to your car and shine it on the waterpump. does the metal look the same color as the rest of the accessories or does it look a little bit cleaner/shinier. if its not cleaner/shinier were talking about an older pump than just the last timing belt change, and generally they go about 1.5-2 timing belt intervals before they tear apart internally, lock up, and kick the timing belt and several engine covers that the belt usually rips right through. Just having it not push coolant and thats it would be a huge save actually, althouth there may be plastic pieces throughout the cooling system now... make you wonder if it was related to your replaced radiator as thats maybe when the pump was starting to fail.

you can DIY on the timing belt and waterpump if you are used to turning a wrench and have the manual and patience to follow every step. if not you can find a better deal than that rwd toyota/lexus v8's are usually in the 6-800 range with waterpump depends on the place and special also.

oaksc400

So I finally had some time and took her to a nearby shop. They did the combustion gas test and it came back positive for signs of BHG. He told me it was a small crack for now, either rip the engine apart or swap in a used motor. I was devastated, I have already spent close to $4000 on the car itself and new plugs/tires. Oh, did I forget to say I bought the car 12/13/14. I tried some head gasket sealer and after running the car for 50 minutes like the instructions said, I cut the car off and came back to check the reservoir tank. It was still full of fluid, can it be possible to have a clogged tank? Should I get the motor or junk it? What do you guys think?

Thanks

suprarale

In your first post on this thread, you mentioned that the heater did not work. You also mentioned there are no visible leaks. I assume that there is no coolant smell from your tail pipe.
Did the heater work before you replaced the thermostat? If so, then there may be air that is in the cooling system preventing proper operation of the heater. If your heater has never worked the short time you have had the car, this could still be the problem.

When the thermostat is replaced, coolant is lost and air enters the system, possibly causing an air bubble in the system such that the heater does not work. This can also cause the car to overheat. Also, the car may have been sufficiently low on coolant when you bought the car, causing air to be drawn into the system during cycles of engine operation and corresponding temperature and pressure fluctuations in the cooling system.

On my Supra, the car nearly overheated in two blocks of driving upon re-installing the radiator. It was air in the lower radiator hose preventing the flow of coolant. I removed the air, resolving the problem.

Research how to remove the air in the system as the solution could be this simple.
Search terms;
air in cooling system
burping the cooling system
filling the cooling system, etc.

Do this in spite of what any shop or mechanic claims the problem is. They often misdiagnose, whether on purpose or not. I hope this helps.