Over the summer my LS overheated while I was heading to Home Depot. Pulled in a parking lot and had my brother come out to help me put some coolant in it (through the throttle body) and see if we could drive it but it was still overheating. Long story short it was very difficult to find a shop that wasn't booked out a full 4 days or more and I ended up taking it somewhere I normally would not have gone. A comment was made about someone drooling over my car which instantly made me think of someone wanting to do a VIP build on my perfectly stock LS and joyriding it after it got fixed. I made sure to pick it up at the end of the day since they were able to get the fan clutch in right away. Based on some reading I had done here I suspected the fan clutch might be the problem so I was pretty happy to pick it up but a mile down the road and she's driving pretty rough. Acceleration is just not there and then the temp gauge started to climb. I let her cool down and then dropped her back off at the shop but they had just closed and no one was around by the time I made it back there after letting her cool off. The next day they told me they had misdiagnosed the problem, the head gaskets needed to be replaced.

Now a lot of people say that's an immediate dump it or engine swap it kind of repair but I hate those two options. Finding a decent engine can be hard as they seem to be pretty desirable. I really don't want to dump it but most shops I call hear what I need done and instantly have a handful of excuses for why they don't want to do it or can't do it. Has anyone here replaced head gaskets on a Gen 2 (Gen 2 Mk II?) LS400? Can anyone recommend a shop in the Phoenix area (East Valley) that WILL do it?

 

It is far, far better to find a used engine. It takes a top flight mechanic to rebuild this engine correct, they are out there but finding such a person/shop is a challenge. If possible get a 2nd opinion. Enter your ZIP here see what's available.

https://www.hollanderparts.com/used-...,-1uzfe-engine)

 

Get a second opinion.
UZ head gasket failures are like unicorns.

 

I would like to know what their deductive reasoning was for the head gasket? What tests did they perform to come to that conclusion? It's very possible it is, but I think I would need verification from test results first.

 

It's almost impossible to have a head gasket failure in a 1/2UZFE. Get a second/third opinion.

 

I would much rather keep the original motor and do the head swap. With all the year to year changes LS400s secretly have I stay away from trusting part interchangeability.

I've done 1UZ head removal on three different VVTi motors. Two were from valve interference and one from overheating. The one from overheating had to have the head milled flat.

If you are comfortable with changing the timing belt, you might be able to do the head removal. Removing the camshafts is the biggest ordeal.

I'd offer help but it's pretty far from Phoenix to Columbus Ohio :-).

 

i agree, get another opinion to see if it's truly the HG. these engine have a particular procedure to get rid of air bubbles in the coolant. air in there will cause overheating too.

next time you see that needle start to climb past half way, crank the heater and see if the temp reduces. also if you have no heat at all, that's a sure sign of air in the coolant.

 

Edit: Assuming that it is: Any idea what it could be worth. Dumping it is on the table, won't have covered parking for it starting in January. I would prefer to sell to someone here not because I would get more money from someone that loves them but hopefully to put her back on the road by selling at a good price. Above average condition on interior and exterior. 206K miles. My uncle had an insane amount of work done about 1.5 years ago I'll add that list.

I had read this many times here, this is my go to one stop shop for getting a rough idea of what a problem might be like my weird telescoping steering wheel noise. I got a second opinion from another mechanic but he seemed unsure. He was expecting to see smoke from the exhaust and I have never seen any smoke of any color. I know that is not always present with a blown head gasket but the look on his face said "I haven't found anything to diagnose this with anywhere near 99% certainty"

Driving it;
Would driving for quite a while with the engine overheating make it more likely to happen? I had been on the highway for 10+ miles and was talking to my friend in the passenger seat. It was as I was getting off the highway to pull into Home Depot (directly past the exit ramp) that I noticed the needle was maxed out or just shy of being maxed out. Rather than hit the brakes hard and pull over at the top of the ramp I chose to continue up the ramp (green light), make my right turn and the first entrance on the right was into Home Depot so perhaps 1/4 mile but I can't be sure when the car began overheating as I only glanced down to check my speed while on the highway. Eyes stayed on the road due to the amount of **** falling out of trucks and trailers in the early afternoon.

The car hasn't really been driven since that shop I used gave me the bad news but I definitely notice there is some kind of slow clunkiness accelerating but it frees up after a few seconds. I'd have to drive it paying attention to the gears if you wanted to know exactly but I think 2nd/3rd going 15mph to 30mph. A couple times a month I drive it like a grandma 1.3 miles to my brother's house and back (never did it during the heat of the day) or I will drive it to the front of my complex to get the mail. Pulled the battery out to charge it on my balcony last month.

Irrelevant:
Side note: Duralast doesn't put Amp Hours on some of their batteries and its really freaking obnoxious to know I've put 25Ah in but not know the max capacity/how much more to go. Someone that claimed they worked for Johnson Controls said it is a 55Ah battery. Friend forgot to switch off my DIY upper glove box charging panel. I made a piece of black ABS plastic to fit in one of the upper glove box storage areas that is on a constant circuit with a USB A+C charger, 12V cig port, and a switch. I don't use my ashtray 12V plug, I installed the same A+C (18W QC3.0+20W PD+Voltmeter+On/Off Switch) inside my center console but it was annoying as could be to have passengers blocking access with their elbow to the on/off switch down below so I said to hell with passenger comfort, I'll put something right in front of them. If I keep this car I'm going to add a magnetic Qi wireless charging pad to one of the top skinny storage slots simply because retention is an issue

 

Didn't even ask. Wouldn't trust them to know their head from their ***. It's just been difficult to get my car looked at. The second I say "looking for a second opinion because the head gaskets on the LS400 are pretty indestructible" half the shops stat with "we can look at it but.....replacing head gaskets isn't something we advise doing, just swap the engine, if you don't swap the engine the car might still run like ****" just excuse after excuse to not do the repair I want. If I tow it somewhere to have it looked at I would prefer that shop be the place that does whatever repair I decide on.

 

That's the catch, I am not comfortable doing the timing belt. The mobile mechanic that came to look at it and was just overall unsure said he'd do an engine swap for me but wasn't interested in committing to head gaskets. He flat out admitted I should look for someone that knows the LS400 inside and out.

 

Kinda sounds like the Home Depot on Country Club just south of the 60..?

 

Have you tried refilling/topping off coolant and are you sure it wasn't overheating due to a hot air pocket in the system? its VERY easy to trap air in these cars and best to bleed out all the air with a vacuum bleeder as they can be difficult to get right using traditional means.

 

Good advice here. It's normal to get air in the system periodically. On both my other LS400s (93 and 94) I've had a hell of a time getting air out of the system after other repairs.
But funny thing on my now 93, after doing the timing belt job and filling the coolant from fill hole on top of thermostat housing I had no air bubbles. Didn't even have the front of the car jacked up higher when I filled it.
Thing is, ya never know if you have air unless you try to bleed it out and your troubles go away. Sounds like you do have air in there. Best, and cheapest, way is to bleed first and go from there. Doesn't cost ya anything except a half hour of your time.
I also agree with everyone saying these head gaskets do not fail, at least I've never heard of one failing.