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Would there be any downsides to by-passing the heater core? I plan on running it like this until around November (or when we start getting snow Tongue). Thanks.

Rick
There isn't a real downside. The issue is do you want to replace it when it's 85* or 25*? [Image: biggrin.gif]

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NATO Member. it's not a vice, it's an obsession
"The nice thing about each new day is nobody ever used it before" Barnaby Jones
88 TC X 2, 86 SVO, mods list at
http://www.turbotbird.com/showroom/pd_88tc.htm
LOL Well, I at least want to do this just to make sure it's my problem. I went down the road yesterday (keep in mind my car overheats after 10 minutes of runtime) to find my grandfather. When I got about 15 minutes away, the guage was pegged. So I turned around and made it all the way until I got a mile from my house. I had thought until yesterday that my thermostat may be part of the problem, but it's working. Once I stopped the car, I turned the engine off, but left the key on so the fan would stay running. I popped the hood after a couple minutes and felt the upper radiator hose, and I could feel the water flowing, so the t-stat's fine. So, out of everything I thought when I got the car, I've got two options left; the heater core and the head gasket. Since I'd rather bypass the heater core and be able to drive the car for awhile [Image: biggrin.gif], I'm hoping it's the heater core! [Image: wink.gif]

Rick
Are you going to bypass your heater core because the car is overheating? A plugged heater core will have no affect on the cooling system of your car. If it overheats that quick you could be looking at a headgasket, if youve already cked all the normal stuff.(radiator,thermostat,fans,air in the system)

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oldone
88 Maroon TC 5 speed
K&N Filter
Gillis boost valve
Are your fans still hooked up like they came from the factory? Check your fluid level when the car is cool and check your oil level after the car has sat for a while. When your car gets hot and you pop the hood, can you see water spewing from anywhere? Seems like stupid suggestions, but it just might be something easy. If your fans are hot-wired, make sure they are blowing in the right direction. Why would you suspect your head gasket? Is water blowing out the side of the engine, or does your oil look like a milk shake? Just a few things to check.

Kev
Your T-stat could be sticky or not opening all the way. I think you need to do some more investigation. Run it with the radiator cap off and see if you get any air bubbles in the coolant - a sign of blown HG. When it hot per the gauge, stick a cooking thermometer in it and see what it really is. When your temp gauge is pegged, is the oil pressure gauge and fuel gauges also reading higher than normal? That could mean your instrument voltage regulator (IVR) is faulty,

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NATO Member. it's not a vice, it's an obsession
"The nice thing about each new day is nobody ever used it before" Barnaby Jones
88 TC X 2, 86 SVO, mods list at
http://www.turbotbird.com/showroom/pd_88tc.htm
"Are you going to bypass your heater core because the car is overheating? If it overheats that quick you could be looking at a head gasket, if you've already checked all the normal stuff."

I'm figuring either the heater core or the head gasket. I figure I'd try this to mainly rule out one or the other.

"Are your fans still hooked up like they came from the factory?"

Yes, and it works fine.

"Check your fluid level when the car is cool and check your oil level after the car has sat for a while."

I have been using water, but it always stops using it at about halfway down the radiator. Oil level is perfect. Hardly uses any oil at all.

"When your car gets hot and you pop the hood, can you see water spewing from anywhere?"

The only place I've ever noticed water leaking is from the turbo. Not sure if it's from the inlet or outlet.

"If your fans are hot-wired, make sure they are blowing in the right direction."

The fan isn't hot-wired, but it is blowing in the right direction and a good amount of air.

"Why would you suspect your head gasket? Is water blowing out the side of the engine, or does your oil look like a milk shake?"

Basically, I'm trying to narrow everything down. The only two things I can think of are the head gasket and the heater core. The oil looks perfect. No water in the oil or oil in the water. No water blowing out anywhere other than the turbo. By the way, it's not leaking alot of water from the turbo line, either.

"Your T-stat could be sticky or not opening all the way."

As far as I can tell, the thermostat seems fine. I'll change it just for good measure if bypassing the heater core doesn't work.

"Run it with the radiator cap off and see if you get any air bubbles in the coolant - a sign of blown HG."

I didn't see any bubbles when I had the cap off and the car running, but I'll check that again.

"When it hot per the gauge, stick a cooking thermometer in it and see what it really is."

Damn, now I have to go buy a cooking thermometer! Tongue

When your temp gauge is pegged, is the oil pressure gauge and fuel gauges also reading higher than normal? That could mean your instrument voltage regulator (IVR) is faulty."

My oil guage always reads high, but only for the first couple minutes of running. Then it comes down as the car warms up and the oil thins out. That's ok, right???

Rick
My oil guage always reads high, but only for the first couple minutes of running. Then it comes down as the car warms up and the oil thins out. That's ok, right???

The oil pressure going down after it warms is normal.

"I have been using water, but it always stops using it at about halfway down the radiator.

Im not sure what you mean by that. If your saying you always lose water until you only have only half a radiator full then you have a definite leak somewhere and it should be obvious. Have you changed the water pump?

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oldone
88 Maroon TC 5 speed
K&N Filter
Gillis boost valve
No, I haven't changed the water pump. I don't see any leaks other than the water line at the turbo. That's the ONLY leak I can see at all.

As far as using water, yes. I meant that I can put it in, and after running for about 10 minutes (about as long as it takes to get pretty hot), the radiator is half full. That's where it stays, though. It doesn't get any lower than that.

Rick
Quote:Originally posted by 86tc:
No, I haven't changed the water pump. I don't see any leaks other than the water line at the turbo. That's the ONLY leak I can see at all.

As far as using water, yes. I meant that I can put it in, and after running for about 10 minutes (about as long as it takes to get pretty hot), the radiator is half full. That's where it stays, though. It doesn't get any lower than that.

Here's my two cents.

Okay, I assume you know that the pressure in the system is what keeps the water from boiling at 100 degrees C, and allows it to get up to over 200 degrees C without boiling, right? Sounds to me like the leak in the turbo water line is letting the system vent, preventing the pressure from building. So, the water is boiling, and that pressure is forcing the water out of the turbo line leak. The leak would look minor, since the coolant is being forced onto the exhaust manifold, where it will be rapidly boiled away, if it isn't forced out of the leak as steam, already.

I had a very small leak where the screw-in connector for the upper water line wasn't tight, and the car was getting a lot hotter a lot quicker than it should have. I suspected a leak, but couldn't find it. I finally figured it out by looking at the white residue on the exhaust manifold, and trying to tighten all of the connections that were near that area. The car doesn't run nearly as hot, now, and the oil pressure gauge doesn't drop to the bottom.

I think that the water won't drop more than halfway down the radiator because that would be about the same level as the water pump and water leak, right? Is it possible that the water pump is pumping air by that point?

Hope this helps.

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Mike Walsted - NATO member
1986 5-speed TurboCoupe and 1985 5-speed XR7

[This message has been edited by Walsted (edited 09-02-2002).]
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