Coolant level?
Thread Starter
Intermediate
Joined: Mar 2004
Posts: 34
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From: Red Deer AB
Coolant level?
Does the coolant in your C4 (specifically an 86) stay right at the top of the rad? I've noticed my coolant light seems to come on and go off while I'm driving. Naturally I added more coolant to top it off, but the light comes back, and I notice I always seem to go down a couple inches from the very top. I do see that what appears to be the coolant sensor is very high on the rad, but the coolant must go somewhere (perhaps just to the bottle). I've pressure tested the cap (looses only 0.5 pounds at 15lbs initial over 5 minutes) and the system itself (looses 2 pounds at 15 lbs initial over 5 minutes). Given the relatively low pressure losses, I am hesitant to consider anything serious like a head gasket or cracked block, but I am a little worried. I think I'll keep an eye on it and see if it goes down much further if I don't top it off, but have to keep a real close eye on it. It may be as simple as a bad sensor, but the fact that I do loose an inch or two of coolant does worry me somewhat.
Thoughts/opinions? :confused:
Thoughts/opinions? :confused:
Race Director
Joined: Sep 2000
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From: The Top of Utah
Re: Coolant level? (Canucklehead)
Have you "burped" the system? A couple of ways is to rev the engine to 2000 rpms while filling. Another is to raise the car so the filler neck is the highest part of the cooling system. Raising the front and revving make a good combination. IF you are getting the system full, it should never fall. You are shouldn't be losing it to the overflow tank. Look at where the overflow tube is attached. It shouldn't fall below that. With a properly sealed system and a good cap, the coolant level shouldn't vary. At it heats, the water expands and blows into the overflow tank. As it cools, the drop in pressure sucks it back into the rad. If you are not maintaining a level, the first thing to check, is the cap. It could send coolant to the tank and not siphon it back. But then, with your monitoring of the rad level, the recovery tank would eventually overflow. Good luck, and...
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Pro
Joined: Sep 2003
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From: charlotte nc
Re: Coolant level? (Canucklehead)
The coolant level inside the RAD on my 86 is always up to the top to the point that it will spill some coolant if I take the cap off (cold, naturally). This has been true even though I had a coolant leak at the intake. The overflow tank would go down over time but the Radiator would stay full and the coolant light stayed off as long as there was sufficient coolant in the recovery tank . I have since fixed the leak . Have you tried drilling four 1/16 " holes around the flange of your thermostat? That will positively bleed air out of your system. I had the same coolant light off/on problem until I drilled the Tstat. Good Luck :cheers:
Racer
Joined: Mar 2004
Posts: 252
Likes: 1
From: Troy Illinois
Re: Coolant level? (CFI-EFI)
I have a 1985 and am having the same problem. No light goes on, dont know if my car has a low coolant warning light, but I lose a little coolant and have a very slight antifreeze smell. I am not getting antifreeze in the oil and my exhaust is normal. I must have a small leak.
I just got the car in January and have read that these cars have problems with small antifreez leaks. I put a bottle of Bar's Stop Leak in and plan on waiting to see if that helps. As long as the antifreez is not getting in the oil or cylinders and the car is not overheating, a small external leak should not hurt anything in the short term. If the stop leak doesn't work I'll take it into the shop I guess. :confused:
I just got the car in January and have read that these cars have problems with small antifreez leaks. I put a bottle of Bar's Stop Leak in and plan on waiting to see if that helps. As long as the antifreez is not getting in the oil or cylinders and the car is not overheating, a small external leak should not hurt anything in the short term. If the stop leak doesn't work I'll take it into the shop I guess. :confused:
Thread Starter
Intermediate
Joined: Mar 2004
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From: Red Deer AB
Re: Coolant level? (CFI-EFI)
Thanks for the info. I just had the radiator replaced so that's why I was a little worried (thinking perhaps I had a bigger problem). I don't think loosing 2 pounds of pressure over 5 minutes would be symptomatic of a head gasket/cracked block, would it? I would expect a lot worse loss of pressure for something like that. I do know that even when I add coolant to the rad, that it will bubble a bit, and if I wait, go down a touch, then I can add more (eventually, the bubbles go away and it will stay right full until I actually run the car). No tell tale signs of serious problems either (no external leaks, no white smoke except for early morning startup here in the Great White North). Any thoughts on where the air would be getting stuck, though? Seems odd that it keeps going down by roughly the same amount. Of course, who am I to really tell. Only got the Vette a week and a half ago :rolleyes: Just trying to make sure I don't have any serious problems before going for the more optional type work. Got a phone call and my new Firehawk tires are in, so gotta pick those up sometime :D
Race Director
Joined: Sep 2000
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From: The Top of Utah
Re: Coolant level? (Canucklehead)
I am not familiar with what is and isn't accetable, pressure drop wise. Your numbers would put me on alert. If nothing else, buy a new cap. Once it is full, and the bubbles stop, it should remain full.
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Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: Coolant level? (Canucklehead)
IF the system is full, and IF the cap is maintaining a seal under both pressure AND suction, AND the level drops, you have a leak. It is THAT simple.
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Thread Starter
Intermediate
Joined: Mar 2004
Posts: 34
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From: Red Deer AB
Re: Coolant level? (CFI-EFI)
Hmmm, well, I know I don't have a visible external leak, and I don't see any white smoke, so that should be okay. How do you see if you're getting coolant in the oil? Only thing I can think of is to drain it, and given that I just changed the oil, that doesn't sound like fun (but if I gotta, I gotta). Any other way to see if coolant is getting into the oil? That's my concern that I have a coolant leak, but I'm just not seeing WHERE it's going.
Race Director
Joined: Feb 2003
Posts: 11,397
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From: Rockledge Florida
St. Jude Donor '07 thru '14, '24
Re: Coolant level? (dwestsr)
:iagree: I just replaced the intake manifold caskets today & at the same time replaced
the thermostat with a hypertech 160. as soon as I started the car (86 coupe) I had the
low coolant light. I took the stat back out & drilled 2 1/16" holes put it back together & the
lite is gone.
the thermostat with a hypertech 160. as soon as I started the car (86 coupe) I had the
low coolant light. I took the stat back out & drilled 2 1/16" holes put it back together & the
lite is gone.
Thread Starter
Intermediate
Joined: Mar 2004
Posts: 34
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From: Red Deer AB
Re: Coolant level?
Think I may have found it, and I'm an idiot :D
I was looking at the wrong spot for where the low coolant sensor was located (I did mention I was new at this, didn't I?). Turns out the low coolant sensor is actually LOWER on the rad than where I was looking and the coolant doesn't get THAT low. So our guess right now is nothing more serious than a bad sensor. Gonna order a new one up tomorrow. Now just have to keep an eye on the actual coolant level to see if my 2 pound drop in pressure is going to actually turn into anything other than my own paranoia :jester
I was looking at the wrong spot for where the low coolant sensor was located (I did mention I was new at this, didn't I?). Turns out the low coolant sensor is actually LOWER on the rad than where I was looking and the coolant doesn't get THAT low. So our guess right now is nothing more serious than a bad sensor. Gonna order a new one up tomorrow. Now just have to keep an eye on the actual coolant level to see if my 2 pound drop in pressure is going to actually turn into anything other than my own paranoia :jester
Instructor
Joined: Aug 2003
Posts: 139
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From: South Cave, Brough East Yorkshire
Re: Coolant level? (Canucklehead)
Coolant in oil - the oil looks milky - sort of like salad cream / mayonaize - but i don`t know how much coolant it takes to make it look like that.
Good luck
Dom
:seeya
Good luck
Dom
:seeya