Throw in the towel? Overheating w/ blown head gasket

[Roads.zx]

The car has a history of overheating and blown head gaskets; both before and after an engine rebuild several years ago. The engine was rebuilt due to an oil sludge problem. With the latest overheat and probable blown head, I am about to throw in the towel unless I can gain some confidence as to what is causing the overheating in the first place.

While overheating due to a blocked catalytic converter is not a common topic in this forum, it is frequently discussed topic on the internet. If I knew that one or both converters were bad I'd repair the car; otherwise we're looking at a donation to the junkyard.

The overheating is not due to low fluid levels and tends to occur without warning after coming to a stop or near stop (fans and radiator are okay). I recently felt the car was losing power so I changed plugs, rotor, cap, and wires. The car was definitely peppier and was driven 300 miles cross country with no problem but a week later she blows.

1995 Camry 5SFE 2.2L 155K

[zythr]

Whoever did the rebuild might have done a lousy job. Keeping or junking the car depends on how much you want to spend on it, and if you like it. Only you can make that decision.

[Mike Gerber]

"The engine was rebuilt due to an oil sludge problem."

The early generation 5SFE engines used on the 92-96 Camrys were pretty hearty. Sludging was very rare. This leads me to believe that this car did not have much maintenance done to it during it's lifetime. That probably includes the cooling system too. At first I was thinking a clogged radiator, but that would show up more with high speed driving and you said "it was recently driven 300 miles cross country with no problems." Did anyone check for a cracked head or block before the engine was rebuilt?

One more thought thinking along with you on the converter, can you disconnect the exhaust system just before the converter and drive it around for a few moments like that. It will certainly be loud, but I would be curious to find out if it overheats like that. That would tell you if a clogged converter is causing the problem. You have little to lose if you're going to junk the car.

Good luck.

Mike

[Roads.zx]

The car was originally purchased used from Toyota dealership. I have done my best to maintain the car in excellent condition. I like the car a lot; but, if I can't feel reasonably comfortable it won't stop overheating I won't keep the car.

When the engine was rebuilt everything was checked or replaced (mostly replaced) with the exception of the catalytic converters. The car ran great for a year when the head gasket blew without warning. The head was overhauled and a rebuilt distributor installed. The car was then restricted to city driving and drove okay for a few years until the recent loss of power, tune up and blow up.

After the latest overheat, I removed the thermostat and drove the car for 20 to 30 minutes. The temperature stayed a little below normal and then suddenly the "Check engine" light came on and the car quit (simultaneously). Car had to be towed to shop (different shop) where I was told the head gasket was blown and the distributor needed to be replaced. They got the car running and I brought it home. Now it won't start and so I've already started dis-assembly. If I'm going to fix it I'll have to do the work myself.

I've removed the cats and sent photos to a cat company for their opinion.

[ghettosled]

ive never heard of a blocked cat only cause problems when the engine RPMs are down like when you close to or at a stop. blocked cats typically choke the motor when the RPMs are up and more exhaust is shoved through then what is able to pass.

since your car is fine running on the highway with the wind blowing through, and you said your radiator fans are working as they should, i would get a infared thermometer and check different spots on the radiator. sounds like your coolent isnt being cooled sufficiently when idling. if there are clogged channels in the radiator, you will see cold spots with a thermometer and enough coolent isnt beeing cooled before being pumped back into the engine.

now what i typed this, something else to consider along the same lines. if your water pump isnt pumping sufficiently, then you arent circulating as much coolent as needed when idleing. ive read some aftermarket water pumps have plastic fins on the impeller that can break over time and therefore not pump enough fluid.

[Mike Gerber]

"something else to consider along the same lines. if your water pump isnt pumping sufficiently, then you arent circulating as much coolent as needed when idleing. ive read some aftermarket water pumps have plastic fins on the impeller that can break over time and therefore not pump enough fluid."

Good thought ghettosled.

Mike

[Roads.zx]

I like your water pump theory of broken fins; I'll be anxious to check it out when I get there.

Cat company says both converters are most likely bad but is concerned that I address what caused them to deteriorate before installing new. With all the oil the car must have burned during it's sludge phase (prior to rebuild) I'm confident that wasn't good for the converters;' but, I've always passed inspection here in Texas.

A couple interesting notes:

1) Car had been running with higher than normal exhaust noise. I thought we had a pin hole leak in exhaust; but, after inspection, no holes.

2) Bolts were tight but there was movement between secondary cat pipe and primary cat and primary cat to exhaust manifold. Pipe bolts appeared burned or rusted or both. Exhaust manifold bolts came off easily; perhaps too easily.

Could back pressure be pulling the pipes apart? Could air leaks around pipe connections allow the car to run at highway speeds even though Cat is restricted?

These are my theories. Still dis-assembling.