Coolant reservior boiling
Thread Starter
Burning Brakes
Joined: Jul 2001
Posts: 902
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From: Glen Allen, VA
CI 3-4-6-8-9 Veteran
Coolant reservior boiling
Tried the search feature but nothing came up...
Here's what's happening on my '94. Would appreciate any diagnosis or what I should be looking for.
-The coolant reservior (black holding tank up by the windshield) is boiling over when sitting idle with no heat on when engine is hot. When I turn on the heat, it calms down. It appears to be about 4/5th full.
-The overflow tank down by the bumper is too full (not by overfilling by me).
-The fluid is filthy -almost muddy- which it shouldn't be. Just checked a few months back.
-Operating temps are running about 10 degress warmer than normal.
Anybody run across this before? Thanks for any help. :cheers:
Here's what's happening on my '94. Would appreciate any diagnosis or what I should be looking for.
-The coolant reservior (black holding tank up by the windshield) is boiling over when sitting idle with no heat on when engine is hot. When I turn on the heat, it calms down. It appears to be about 4/5th full.
-The overflow tank down by the bumper is too full (not by overfilling by me).
-The fluid is filthy -almost muddy- which it shouldn't be. Just checked a few months back.
-Operating temps are running about 10 degress warmer than normal.
Anybody run across this before? Thanks for any help. :cheers:
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Re: Coolant reservior boiling (TimC)
Not real familiar with your set up, I have an '88
But it does sound like either a thermostat, a water pump. Have you checked the hoses? Both heater hoses should be equally hot and both the upper and lower radiator hoses should be equally hot.
If the top rad hose is cool, check thermo first, bad rad hoses second and waterpump third.
If heater hoses aren't equally hot, flush the heater core
Turning on the heater is sort of like turning on the fan on a small radiator...it does some good!
:seeya
:steering:
But it does sound like either a thermostat, a water pump. Have you checked the hoses? Both heater hoses should be equally hot and both the upper and lower radiator hoses should be equally hot.
If the top rad hose is cool, check thermo first, bad rad hoses second and waterpump third.
If heater hoses aren't equally hot, flush the heater core
Turning on the heater is sort of like turning on the fan on a small radiator...it does some good!
:seeya
:steering:
Instructor
Joined: Dec 2003
Posts: 244
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From: Katy
Re: Coolant reservior boiling (TimC)
I had what sounds like a very similar problem. Do you have a slight amount of coolant loss around the the radiator cap?
Mine developed a leak around the neck of the tank. Replaced the tank, no more problems.
Mine developed a leak around the neck of the tank. Replaced the tank, no more problems.
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Re: Coolant reservior boiling (TimC)
The fact that you describe the coolant to me muddy-looking is reason enough for you to have the cooling system flushed thoroughly before you look for problems. Gunk in the system can cause a variety of things: sticky thermostat, radiator, heater core or block passages plugged up and possibly a bad pressure cap.
The expansion tank should not overflow. Excess coolant should be going to the overflow tank at the RF fender well. Turning the heat on and dropiing the level in the tanks sound like the system is blocked somewhere. The expansion tank should always be full (to the top of the tank).
Pull the dipstick and check for water in the oil. Is the oil muddy looking like the coolant? May be a head gasket leaking or a crack somewhere. Get the coolant flush done and have a pressure test done at the same time. Replace the pressure cap and clean out the overflow tank and refill it to the proper mark. Let us know what happens after that.
The expansion tank should not overflow. Excess coolant should be going to the overflow tank at the RF fender well. Turning the heat on and dropiing the level in the tanks sound like the system is blocked somewhere. The expansion tank should always be full (to the top of the tank).
Pull the dipstick and check for water in the oil. Is the oil muddy looking like the coolant? May be a head gasket leaking or a crack somewhere. Get the coolant flush done and have a pressure test done at the same time. Replace the pressure cap and clean out the overflow tank and refill it to the proper mark. Let us know what happens after that.
Thread Starter
Burning Brakes
Joined: Jul 2001
Posts: 902
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From: Glen Allen, VA
CI 3-4-6-8-9 Veteran
Re: Coolant reservior boiling (c4cruiser)
I'll flush it, check it out and report back. I didn't check my oil, but just changed that two weeks ago and it looked fine.
Thanks for the help. :cheers:
(Heya Jack!)
Edit: JMiller, yes it was overflowing by the radiator cap. The overfill tank was as full as it could be and it wasn't draining.
[Modified by TimC, 10:10 PM 1/21/2004]
Thanks for the help. :cheers:
(Heya Jack!)
Edit: JMiller, yes it was overflowing by the radiator cap. The overfill tank was as full as it could be and it wasn't draining.
[Modified by TimC, 10:10 PM 1/21/2004]
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Le Mans Master
Joined: Nov 2002
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From: Corvette valley Georgia
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Re: Coolant reservior boiling (TimC)
You didnt give the mileage but its safe to say that the coolent has not been changed in a while.
First change out the coolent and flush the system and if you can remove the knock sensors from both sides and remove all coolent.
Also check the outside of the radiator and see if debris is blocking the air flow thru the core.
A good idea also is to change the thermostat out and the pressure cap too.
First change out the coolent and flush the system and if you can remove the knock sensors from both sides and remove all coolent.
Also check the outside of the radiator and see if debris is blocking the air flow thru the core.
A good idea also is to change the thermostat out and the pressure cap too.
Le Mans Master
Joined: Aug 2003
Posts: 9,884
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From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
Re: Coolant reservior boiling (grapeknutz)
You didnt give the mileage but its safe to say that the coolent has not been changed in a while.
First change out the coolent and flush the system and if you can remove the knock sensors from both sides and remove all coolent.
Also check the outside of the radiator and see if debris is blocking the air flow thru the core.
A good idea also is to change the thermostat out and the pressure cap too.
First change out the coolent and flush the system and if you can remove the knock sensors from both sides and remove all coolent.
Also check the outside of the radiator and see if debris is blocking the air flow thru the core.
A good idea also is to change the thermostat out and the pressure cap too.
Instructor
Joined: Dec 2003
Posts: 244
Likes: 0
From: Katy
Re: Coolant reservior boiling (TimC)
Sounds exactly like the problem I had.
They found a small hole in the sleeve (kneck) of the tank which was allowing air to escape thus allowing the system to let pressure out and boiling in the tank.
The new tank was something like $40 and is pretty simple to replace. I had the dealer do this, as I tried everything I knew. New cap, flush etc. No luck until the new tank was installed. Dealer got me for $150 to find the problem and fix
:nonod:
[Modified by jmiller, 11:04 PM 1/21/2004]
They found a small hole in the sleeve (kneck) of the tank which was allowing air to escape thus allowing the system to let pressure out and boiling in the tank.
The new tank was something like $40 and is pretty simple to replace. I had the dealer do this, as I tried everything I knew. New cap, flush etc. No luck until the new tank was installed. Dealer got me for $150 to find the problem and fix
:nonod:
[Modified by jmiller, 11:04 PM 1/21/2004]
Team Owner
Joined: Apr 2001
Posts: 22,267
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From: Dallas TX
Re: Coolant reservior boiling (TimC)
Check your t-stat and your pressure tank cap. Shouldn't be boiling in winter with a stock size engine. My stroker boiled sometimes... just got too hot for 100+ temps with stock cooling system. Also verify that your anti-freeze/water mixture is proper.
goodluck!
goodluck!
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Re: Coolant reservior boiling (TimC)
I'll flush it, check it out and report back. I didn't check my oil, but just changed that two weeks ago and it looked fine.
Thanks for the help. :cheers:
(Heya Jack!)
Edit: JMiller, yes it was overflowing by the radiator cap. The overfill tank was as full as it could be and it wasn't draining.
[Modified by TimC, 10:10 PM 1/21/2004]
Thanks for the help. :cheers:
(Heya Jack!)
Edit: JMiller, yes it was overflowing by the radiator cap. The overfill tank was as full as it could be and it wasn't draining.
[Modified by TimC, 10:10 PM 1/21/2004]
I am sorry, I just realized it was you :bb :bb :bb
Often I don't check who the poster is when i am in this section!
Let me know how you make out!
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:seeya
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