Coolant level always low
Thread Starter
Drifting
Joined: Dec 2012
Posts: 1,504
Likes: 73
From: Georgetown TX
Coolant level always low
89 l98
Took off my TB to clean it and now it seems I have to keep adding coolant. Seems like I have added more than it should even hold total. I gave replace cap, added coolant to radiator directly and to recovery tank. After it cools down Radiator is low and recovery tank empty. Can find no leaks. I think I must have air block but don't know how to fix it
Took off my TB to clean it and now it seems I have to keep adding coolant. Seems like I have added more than it should even hold total. I gave replace cap, added coolant to radiator directly and to recovery tank. After it cools down Radiator is low and recovery tank empty. Can find no leaks. I think I must have air block but don't know how to fix it
Team Owner
Joined: Sep 2001
Posts: 62,154
Likes: 1,731
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
I would burp the system once to be sure that isn't it, but then i'd drain the coolant and the oil and look for signs of head gasket problems.
To burp it, you would need to let it heat up to t-stat opening temp, which is 195F on the 89, with the radiator cap off. Then slightly rev the engine so it sucks it down, add coolant, replace cap and fill reservoir to the right level. If it is then still going low, could be the head gasket, could be a pinhole vapor leak, etc. Sometimes a leak will not show itself until the engine is hot.
To burp it, you would need to let it heat up to t-stat opening temp, which is 195F on the 89, with the radiator cap off. Then slightly rev the engine so it sucks it down, add coolant, replace cap and fill reservoir to the right level. If it is then still going low, could be the head gasket, could be a pinhole vapor leak, etc. Sometimes a leak will not show itself until the engine is hot.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Air blocks are greatly over-rated (yeah, I know, I have read all about the gigantic bubbles).... a bubble
would just interrupt coolant flow, not cause coolant to leave the system.
Check ALL hoses, and hose ends, and rad cap gasket.
Thread Starter
Drifting
Joined: Dec 2012
Posts: 1,504
Likes: 73
From: Georgetown TX
Found a hose leaking on the pass side of TB , but still getting low coolant light even though it's not low. If I drive aggressive the light will go out for a while but comes back later. Got a new coolant sensor coming and will try that
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Not unusual. Park it on hill, nose up and top off the radiator after the t/stat has opened.
Race Director
Joined: Mar 2015
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Racer
Joined: Oct 2012
Posts: 265
Likes: 5
From: Phoenix AZ
89 l98
Took off my TB to clean it and now it seems I have to keep adding coolant. Seems like I have added more than it should even hold total. I gave replace cap, added coolant to radiator directly and to recovery tank. After it cools down Radiator is low and recovery tank empty. Can find no leaks. I think I must have air block but don't know how to fix it
Took off my TB to clean it and now it seems I have to keep adding coolant. Seems like I have added more than it should even hold total. I gave replace cap, added coolant to radiator directly and to recovery tank. After it cools down Radiator is low and recovery tank empty. Can find no leaks. I think I must have air block but don't know how to fix it
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Drifting
Joined: Feb 2008
Posts: 1,537
Likes: 178
From: NE Ohio
2024 C4 of the Year Finalist - Unmodified
that sounds like an air bubble. It should cycle out after 4 or 5 heat and cools.
Safety Car
Joined: Jan 2014
Posts: 4,017
Likes: 492
From: Poughkeepsie New York
I had the low coolant light issue. The previous owner had the intake gaskets replaced and they never got all of the air out. I jacked the front of the car up as high as I could then brought it up to temp. When the t-stat opened I stuck a socket under the throttle bracket to idle at 2k. Then topped off and put the cap back on. Problem solved.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
The OP posted: "Found a hose leaking on the pass side of TB , but still getting low coolant light even though it's not low. If I drive aggressive the light will go out for a while but comes back later. Got a new
coolant sensor coming and will try that."
The OP posted that he solved the leak problem, but was still getting the 'low coolant light' when the reservoir was full. It would follow that maybe the sensor was faulty. Since he ordered a new sensor, replacement may solve the problem.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
Having air in the system will cause the light to come on, but the low coolant sensors can also go bad..I usually snap off the sensors holding prongs way before mine ever go bad...
..The coolant system will actually purge itself over time like mentioned above, but drilling a small 1/16" hole in the rim of the thermostat will speed up the process..I always drill the hole in any stat I install...
.WW
..The coolant system will actually purge itself over time like mentioned above, but drilling a small 1/16" hole in the rim of the thermostat will speed up the process..I always drill the hole in any stat I install....WW
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 579
Before calling someone stupid, maybe the name caller should learn to read.
The OP posted: "Found a hose leaking on the pass side of TB , but still getting low coolant light even though it's not low. If I drive aggressive the light will go out for a while but comes back later. Got a new
coolant sensor coming and will try that."
The OP posted that he solved the leak problem, but was still getting the 'low coolant light' when the reservoir was full. It would follow that maybe the sensor was faulty. Since he ordered a new sensor, replacement may solve the problem.
The OP posted: "Found a hose leaking on the pass side of TB , but still getting low coolant light even though it's not low. If I drive aggressive the light will go out for a while but comes back later. Got a new
coolant sensor coming and will try that."
The OP posted that he solved the leak problem, but was still getting the 'low coolant light' when the reservoir was full. It would follow that maybe the sensor was faulty. Since he ordered a new sensor, replacement may solve the problem.
Last edited by antfarmer2; May 9, 2015 at 08:20 AM.
Racer
Joined: Dec 2007
Posts: 416
Likes: 3
Directing someone to a video about changing a TEMPERATURE sensor is just wasting that persons time. If I see someone bought the wrong part for their problem I'm not giving them instructions on how to change the wrong part. In fact you did say you think he has a bad TEMPERATURE sensor.
Go read your FSM and talk to your mechanic before giving bad advice.