Head gasket, again?

[Rabbitbunny]

So... same cheap little '92 Prizm, only now I'm driving it 45mi a day. This car sat for 7 years and only has 95K on it.

First I lost a head gasket because I had low fuel pressure and lean == hot.

Then I lost a head gasket because my fan relay died.

Now it has randomly lost the head gasket, for no discernable reason.

What am I missing here?

The water pump is new.

The radiator has been boiled.

The hoses are all new.

The head was crack-checked.

The thermostat is new.

The electric fan system is new.

So... flat 70-75mph for 45 miles and the car is boiling over when I get home.

What's going on here?

Now, the first thing I thought was I botched the gasket install, but that's pretty hard to do on these simple little things. I cleaned both sides with a rag, sprayed them with brake cleaner and let them air dry, applied indian head, waited, laid the gasket on the dowels, laid the head in and torqued it perfect. Granted, I did reuse the old bolts, but I cleaned the heck out of them. Yes, I know what torque to yield is. No, it's not going to matter, I did the FEA and it's only about 0.03% strength lost, so while I do understand why Toyota says to replace the bolts... it's really not needed.

I don't think it was the install... The common theme is that it's always cylinder #4, and the first time it was #3 + #4. So...

Do these cars just lose the head gasket at #4 for fun?

It's not a huge leak, I've got 170 - 170 - 170 - 90psi.

[Scott O'Kashan]

Did you have the cylinder head checked by a machine shop to be sure it didn't warp from the several engine overheating issues? If the cylinder head is warped, the head gasket will fail no matter how many times it's replaced.

[Donald]

Originally Posted by Scott O'Kashan

Did you have the cylinder head checked by a machine shop to be sure it didn't warp from the several engine overheating issues? If the cylinder head is warped, the head gasket will fail no matter how many times it's replaced.

I have been told that these blocks never warp, but I would check it for "true" also.
It is very easy to check the block and head for true. All you need is a 100% straight edge and a feeler gauge. A piece of aluminum angle is what I use for straight edge. That is usually reliable.
If you have any doubt about the head, have a machine shop pressure check it also, it might be cracked. It is worth the cost, and sure beats pulling the head again.

[Rabbitbunny]

Hmm, You're both right, I haven't checked for warping at all. Thanks.

[Scott O'Kashan]

This is assuming the head gasket has blown again. Diagnose that before going to the trouble of tearing it all apart again. You can buy a testing kit that will test the coolant for exhaust gases and that will tell you if the head gasket is blown or not. With an engine overheat, it's not unusual for the aluminum cylinder head to warp. If it has warped, a machine shop may be able to repair it for you.

[Elizle]

I'm losing antifreeze and there is white smoke coming out of my exhaust. I'm probably in the same boat. I need to get a new car so I can have something reliable to drive while I'm fixing my corolla.