Mystery coolant problem - I am baffled????
Thread Starter
TECH Fanatic
Joined: Nov 2001
Posts: 1,064
Likes: 0
From: CA
Mystery coolant problem - I am baffled???? Ok, using coolant like crazy. Car is fine, then after 20mins of REGULAR DRIVING she starts to get hot and I can hear the coolant boiling over, and I lose about a pint or so. No leaks, pressure tests are fine, no smoke, oil analysis was clean, compression test was fine, no smell - NOTHING 
Any ideas?
Any ideas?
TECH Fanatic
Joined: May 2005
Posts: 1,135
Likes: 1
From: The 'Burgh, PA
Just because it is "flowing smooth" doesn't necessarily mean that the proper volume of fluid is flowing over a given period of time. If the system needs flushed, or a bad component is affecting the flow then you will not have enough flow to provide adequate cooling. I would do the following (which really is just routine maintenance, so you are not out anything if it doesn't fix the problem):
1) remove the Tstat and radiator cap.
2) buy some good radiator flush and do a complete flush of the system.
3) replace the tstat and radiator cap with new ones.
This will probably fix the problem. If not, I would then shift my attention to the operation of the fans and water pump. Have you done anything to change your fuel mixture and lean it out? I have seen this cause heating problems as well.
Good luck
1) remove the Tstat and radiator cap.
2) buy some good radiator flush and do a complete flush of the system.
3) replace the tstat and radiator cap with new ones.
This will probably fix the problem. If not, I would then shift my attention to the operation of the fans and water pump. Have you done anything to change your fuel mixture and lean it out? I have seen this cause heating problems as well.
Good luck
Last edited by JohnnyC; Aug 30, 2006 at 11:15 AM.
Trending Topics
TECH Fanatic
Joined: May 2005
Posts: 1,135
Likes: 1
From: The 'Burgh, PA
actually, water cools better than anti-freeze. This is why most race cars run just water. If we could just keep it from freezing and from causing corrosion we could run water only. I doubt the mix is the problem, but a flush and re-fill would allow you to get back to the perfect mix before winter.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
TECH Addict
Joined: Jun 2005
Posts: 2,660
Likes: 14
From: England
If you are loosing water it is:
a) burning it
b) leaking it
I guess the car overheats because of lack of water, rather than overheating then venting water out of the over flow in the header tank.
So this means the water has to be going somewhere. Sadly to me it sounds like a cylinder head gasket. These can go and be very hard to detect, as the won't always contaminate the oil. I had a car last year that had a cylinder head gasket issue, very similar. You could drive for 30 mins or so before the water level got too low and it started to over heat. The oil was 100%. I ran the car for 3000 miles in this condition though before flogging it.
Lastly just check for leaks in the water system, a few months back my DD developed a leak in the radiator, however it would only leak if the car was left ticking over for 15 mins (like in a traffic jam). In normal use you would never have known it was leaking, this took me 2 months to locate and then only by accident as I was helping recover another car and left my ticking over.
a) burning it
b) leaking it
I guess the car overheats because of lack of water, rather than overheating then venting water out of the over flow in the header tank.
So this means the water has to be going somewhere. Sadly to me it sounds like a cylinder head gasket. These can go and be very hard to detect, as the won't always contaminate the oil. I had a car last year that had a cylinder head gasket issue, very similar. You could drive for 30 mins or so before the water level got too low and it started to over heat. The oil was 100%. I ran the car for 3000 miles in this condition though before flogging it.
Lastly just check for leaks in the water system, a few months back my DD developed a leak in the radiator, however it would only leak if the car was left ticking over for 15 mins (like in a traffic jam). In normal use you would never have known it was leaking, this took me 2 months to locate and then only by accident as I was helping recover another car and left my ticking over.
just a few weeks ago one of my friend's blew a geaket on a firebird v-6. no water in oil but with the cap off you could see bubbles.put the cap on and try to drive it and it would overheat.it would also pressurize the coolant so when we tried to remove the cap it would overflow no mater if it was hot and overheating or not.