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Issue after overheating

Hey guys, new member and desperate for some advice.

I was driving to work a few days ago and about 5 miles into my drive my a.c. started blowing hot. Looking at my gauges I saw the temp was as far in the red as it could go and I immediately pulled over. I popped the hood and watched as the radiator cracked, spraying steaming coolant everywhere.

When the car was cool I drove it onto a trailer and hauled it home, at this point the engine ran fine.

I deduced that the water pump was leaking, so I replaced it, the radiator, all the hoses and belts. Afterwards I started the engine and it isn’t running right. I don’t know how best to describe it, but it seems to lack power, as if its not getting enough gas. When I put it in drive or reverse it will go for a moment then shut off.

There are no leaking fluids, the car is running cooler than before and no smoke from the tailpipe.

I went over my work with a fine tooth comb and can’t figure out what the issue might be. For the very brief moment I ran it to get it up on the trailer it ran fine, so figure I must have done something during the replacement of parts.

Any ideas? Head gasket, warped cylinder heads?

Pressure test the cooling system and do a compression test is where to start. Makes sense to inspect any electrical connectors you had to undo to replace the radiator and water pump of course. Especially any involving ground points for the sensors. Replacing the water pump requires jacking the engine, right? Did you follow the factory service procedure instructions when you did that? I expect you fried the engine, and that’s why it isn’t running well now. If you lucked out, you still have to figure out why it overheated. I’m guessing the radiator fan wasn’t spinning when it should have been, likely due to a faulty coolant-temperature switch.

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I followed the Haynes manual which didnt require lifting the engine, although that certainly would have made things easier.
I made sure to reconnect the few electrical connections I had to disconnect, but I suppose I should double check.
The pump was definitely leaking, so I figured that was the cause of the overheating.

What’s the model year of your Prizm?

Its a 1995. 1.6L

One hunch is the head gasket is leaking badly and coolant is getting into the cylinders soon after startup. Pressure test the cooling system - that can be done without running the engine. If you can get the engine to keep running, see if bubbles keep appearing at the open radiator neck. That would be combustion gasses, because of leaking head or head gasket.

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I’ll give this a try tomorrow, thanks.

Since I was messing with the cooling system and belts, is there anyway a problem with those could affect the way the engine is running?

I’m just trying to rule out error on my part and discover where I may have gone wrong.

How much coolant was spraying under the hood? Any chance some of it could have gotten into the ignition system?


I didn’t look for it but that’s quite possible, there was a lot of steam coming from the top of the radiator and it got over a few things.

Quick easy, look at the plugs. Really clean means head gasket leak.

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So I discovered oil in the spark plug wells. No bubbles coming from the radiator, or other symptoms of head gasket issues.
I thoroughly cleaned up the oil from spark plugs and wires but engine issue persists.

Could the plugs have been damaged from overheating engine?

Later this afternoon I’m going to have a friend run a compression test and see what he comes up with.

I continue to think a compression and cooling system pressure test is where to start. There are a couple of things you could check first I guess.

I have a 92 Corolla 1.6L, similar but not identical. On mine there’s a ground connection on the passenger side fender with a connector; it would be a natural thing to undo that connector to make room when working on the water pump. Double check that wire isn’t now dangling. Replacing the radiator and water pump wouldn’t normally do anything that would cause poor idling.

When you did that work did you remove the air intake boot from the air cleaner to the throttle body? If so make sure you installed it correctly, no air leaks etc. There are some vacuum line attachments in the water pump area on my Corolla, so double check none of those has been left disconnected or connected to the wrong spots. There may be a vacuum hose routing diagram on the underside of the hood. Are there any diagnostic codes?

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Thanks for the response. I backtracked again and discovered a hose that came loose from the intake manifold. I must have pulled it loose when I was reaching around with a screwdriver to tighten the hose clamps at the water neck/water pump. I’m quite thankful and relieved that it wasn’t something much worse as this is my only car and ride to work. Those Toyota engines just keep chugging along.


Thanks for letting people hear know about your good result. Congrats!

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Thanks! It was stressful trying to identify the problem but I’m glad it happened since I discovered a few other things that need my attention.

Good work there OP. You are right, the Toyota engines of that era are pretty much bullet-proof. Happy motoring.

If you have something like that happen again, sometimes you can rig up a way to direct a little propane around various spots around the engine. If it starts running noticeably better, you’ve probably found the vacuum leak.

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