I need help from the pit crew (cars, not BBQ)

General Questions
#1

I have a 1992 Toyota Celica convertible. I’ve had it for just over 10 years. I know it needs to be replaced, before it sucks the last penny from between the sofa cushions. I’d like to replace it in my time frame, not the car’s.
But we have a problem. It started over heating about 2 months ago. I took it to a Walt’s Auto service, thinking it needed a radiator flush. I was half right, it needed a radiator. At least that what we paid for. They said they back-flushed the new radiator, replaced the hoses and the water pump. Well, damn, its still over heating.
It doesn’t act like a head gasket, because sometimes, actually most of the time its rock steady. When it does over heat, turning the heater full on brings it down within a minute or so. It doesn’t overheat the first time its driven on a given day. Drive, drive, drive, no problem, just don’t stop. Once it stops, or even if the idle just goes below 1100 RPMs, up goes the temp and I have to leave the heater on the rest of the trip. In other words, taking it back up to freeway speed without the heater being on doesn’t correct the problem.
The other symptom is the RPMs fluctuate at idle. It sounds like the car is breathing. The idle seem a little low to me too, it “breathes” 850 RPMs to 1000.

Ideas? Suggestions? Witty comebacks? Anything?
Hey, thanks in advance.

#2

The first thing to check is the engine coolant level. With the engine cold, take off the radiator cap. It should be full to the bottom of the cap’s hole. If it’s low, there’s leakage that needs to be found and fixed.

Checking the level in the overflow jar is not reliable UNLESS everything’s working right – no leaks, cap functions properly, tubing between cap and jar in good shape, etc. It’s possible to have a leak that, instead of sucking liquid back out of the jar as the engine cools, sucks air in through the leak.

If the engine coolant level is correct, we can discuss other possibilties, but if it’s low, there’s not much point yet. Cooling systems cannot function properly if they’re significantly low on coolant.

#3

We’ve checked the coolant frequently. I was afraid if it boiled over, I’d just be compounding the problem. Coolant level is good.

#4

Does it have a distributor? A bad vacuum advance can cause overheating and a poor idle.

Then again, I think that Toyota had switched to electronic engine management by 1992. I guess that a bad manifold pressure sensor might cause the same symptoms, but I really don’t know.

#5

My next thought is that the electric radiator fan is not functioning. It should come on when the coolant temp reaches about 220 degrees, then go off when it’s down to about 210. Stop and go traffic and idling are when it’s most critical, as there’s no other airflow through the radiator then, but I have seen inoperative fans affect engine temp even at highway speeds. I bet that’s it.

#6

Head gasket is pretty easy to rule out by looking at the oil. Most gasket cases I see turn the motor oil to a dark cholaty brown. If it’s black you’re probably in good shape.

Any reason this problem couldn’t be a dying thermostat? 'course that doesn’t address the idle, but the two issues don’t necessarily have to be related.

#7

My volvo did exactly that. It needed a new thermostat.

Woo. Rhyming and everything.

#8

Sorry, I failed to mention Walt’s Auto replaced the therostat when they put in the new radiator.

Ethilrist Thanks, at least for the :slight_smile:
Gary T You may be on to something. You sparked a memory of my husband’s '91 Nissan. It needed a thermo-clutch. I think its an hydralic clutch that turns the radiator fan. could that be it?
We noticed that most of the plastic/rubber connections are becoming brittle, is that be caused by the heat, or just aging?
Someone suggested we take it back to Walt’s and insist they go over what was done and make sure its all ok. I’m afraid if I take it back they’ll just charge us another $500.00 we don’t have to waste.

#9

Replace thermostat

Have the electric cooling fan tested- or do visible inspection.

I think you are over studying the idle. It probably varied, but you are sensitive to it now. Also, a car that is not operating within the ideal temp range wouldn’t shock me if it didn’t run perfectly…low performance, idle, rough running.

#10

If the Celica has a belt-driven fan, yes. I was assuming it had an electric fan, but now that I think about it, I’m not sure which design it uses. (The fan clutch is sometimes called a thermal clutch – it’s not hydraulic.)

Both.

Surely they wouldn’t charge anything without your approval? Even so, I suspect what you have is not a failure of what they did, but of what they did not do. That doesn’t necessarily mean they erred – if the radiator was plugged up or leaking, and if the water pump was leaking or had shaft looseness or a pitted impeller, they could have caused or contributed to overheating. The hose replacement was likely preventative maintenance, possibly well justified if they were in poor shape. And if most of the time the car doesn’t overheat, they may not have observed any symptoms after the work they did.

On the other hand, they might have misjudged the need for the radiator or water pump, and/or failed to note a detectable problem with the radiator fan operation. I would suggest take it back to them and tell them what you’ve told us. They may or may not have any responsibility for its still overheating, but it shouldn’t hurt to ask.

#11

The thermostat, as I said previously, was replaced with the radiator 2 weeks ago.

Gary T Thank you, my husband will check the fan clutch later today, and I’ll call Walt’s when I get back from the dentist.

Thank you, all for your advice. I’ll let you know how it all works out.

:slight_smile:

#12

Well, Fireman tells me There isn’t a radiator fan How can that be? He tightened the connections, and reset the computer. That didn’t help.
Walt’s was no help at all. They won’t look at it without charging at least 15 minutes labor. I know that isn’t a lot of money, but, Damn, they didn’t fix it the first time, why should I give them more money to not fix it?
While I was driving today I noticed the temp stays down if the RPMs stay over 2000. If they drop below that, even with the heater on, the temp climbs.
Any more ideas?
I test drove a Corvette today, which we’ll pick up on Wednesday.
I can’t really sell the Celica for what its worth if we can’t fix this problem.
(I’d really rather have a horse.)

#13

uhh… there needs to be a radiator fan. otherwise your car would overheat sitting at stoplights when there is no wind passing air over the radiator. since the radiator, thermostat, water pump, and hoses have been replaced, this points to a bad fan or bad thermosensor (if it is an electric fan), or a bad fan clutch if it is engine driven. the other possibility is that you have some sort of blockage in your engine’s water passages that prevents good flow of water at lower rpms.

i think your car has an electric fan. you can test the fan by hard wiring it to a 12v source and make sure it comes on. assuming it is, i would replace whatever tells your fan to turn on.

#14

It can’t be unless it has been removed and left off. The car had a radiator fan when it left the factory. Is it front wheel drive with a transverse engine? If so, it uses an electric fan mounted to the engine side of the radiator. Is it rear wheel drive with traditional fore/aft engine orientation? If so, it uses a belt driven fan (almost certainly with a clutch) mounted to the water pump pulley on the front of the engine. In either case, the fan is immediately rear of the radiator, almost certainly surrounded by a shroud.

Huh? What connections? What for? And how’d the computer get into this? Sorry if I’m being dense, but I don’t see how this relates to the discussion at hand.

That’s disappointing. I think the right thing for them to do is at least do a basic check for the obvious at no charge, but I don’t run the place.

Assuming the newly replaced radiator, water pump, and thermostat are all working properly, the fan is still the prime suspect, particularly if it’s belt driven with a clutch.

#15

Gary T Thanks for coming back.

I meant to come back after I went out to look for myself. It, of course, has a fan. An electric one. The car is front wheel drive.

There were some electrical connections that were loose. He thought it might be that. As far as the computer goes, well, Fireman thinks resetting the computer will fix anything. As a mechanic, he makes a great firefighter… :slight_smile:

The owner wasn’t there the day I called. I’m going to try again on Monday. He seemed pretty reasonable when I originally talked to him. The counterman I talked to Thursday was, I think, a bit lazy.

I pick up the Corvette on Wednesday, so after that, the Celica can be parked until we can find a cure. Then I’ll sell it :frowning:

#16

I am not a professional mechanic but I think there is a big clue here. The only thing that I can think of that might suddenly (key word) work at a certain engine rpm is a water pump. The higher rpm of the impeller can suddenly overwhelm the seal leakage making the leakage irrelevant as far as apparent functioning is concerned.

It is entirely possible that a miscommunication between the employee and the service writer has resulted in you having the same water pump as before. Did you ask to see your old parts?

Just a thought.

#17

No, in fact, we didn’t see the old parts and the rocket surgeon was the one working the day we picked it up. You may have something. I’ll call the owner on Monday and let you know.
Thanks :slight_smile:

#18

I have to agree it now sounds like a water pump-related problem – faulty pump, loose belt driving it, cavitation from a big air pocket or pump cavity corrosion, etc. The shop should check the pump installation and operation at no charge – you paid for a replacement pump, yet still have what appears to be the same symptom. Of course it could be something else entirely, for which you would be liable to pay for the testing and repair, but under the circumstances they should certainly check what they’ve done and affirm those items are okay.

Engine cooling systems, while generally not difficult to work on, can sometimes be very challenging to diagnose. It’s not unusual to need more than one attempt to get cooling system problems resolved.

#19

Well, we took it to a different mechanic, who immediately found the fan switch and sensor were bad. After replacing them, he called to say the temp hadn’t come down as much as he’s expected. He also could hear a noise under the timing cover.
It turns out the water pump had not been part of the Walt’s repair. The water pump and the timing belt are now being replaced.
Another $800 (sigh) Now, I have to find a buyer who appreciates all the work we’ve had to put into it.
Thank you all for your suggestions and encouragement.

#20

Oh! I forgot to mention, we picked up the Corvette yesterday. Oh my, is it sweet!