My 1994 acrua Legend is overheating! =(

Tiny
DOMJANSSON
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  • 1994 ACURA LEGEND
  • 55,000 MILES
I have a 1994 Acura Legend. Recently it has been overheating and is apparently low on fluid. I had an engine swap done at the dealership 50k miles ago ( they also replaced my radiator, heater core, water pump and associated lines). There are no apparent leaks and after I drive it for a while its down about a quart. There is no condensation coming out of the exhaust so I doubt its water jackets. I have done a combustion test to check and see if its the head gasket but the test confirmed that the head gaskets are fine. I revved it in my driveway increasing the heat to around 180 degrees and there is no dripping. I check underneath my car before I leave every morning / night and it's clean as well. Before I leave I make sure to fill it with mixed Anti-Freeze and after driving it for a day or two it routinely overheats and acts low on fluid. I'm baffled as to how its losing fluid and overheating as it is. Any all help would be greatly appreciated.
Tuesday, September 25th, 2012 AT 5:21 AM

19 Replies

Tiny
DOMJANSSON
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Both fans are working perfectly as intended. Forgot to include that.
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Tuesday, September 25th, 2012 AT 5:27 AM
Tiny
KHLOW2008
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Somewhere there is a leak in the cooling system and a pressure test on the system should show you where it is coming from. A dye test would make it easier o detect.

Did you check the interior carpets for signs of coolant? A leak at the heater core would not leak outside.
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Tuesday, September 25th, 2012 AT 5:27 AM
Tiny
DOMJANSSON
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Interior carpets are fine and the heater core is sealed up tight. Didnt notice any leaks from it. I'll have to get a pressure test done. Another possibility is that the engine overheats when the thermostat fails to open completely and I've just been adding excess amounts of anti-freeze? I'm an armature mechanic at best lol. Completely baffled with this.
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Tuesday, September 25th, 2012 AT 5:35 AM
Tiny
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Is the recovery tank overflowing or depleting?
You mentioned a combustion test, you mean a compression test or a chemical test to detect presence of carbon in cooling system?
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Tuesday, September 25th, 2012 AT 5:48 AM
Tiny
DOMJANSSON
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Chemical test to detect carbon / emissions. It came back clean. The recovery tank seems to stay the same but when the car overheats the radiator's basin is low on fluids. Or so I think, unless I've been over-filling it? Doubtful though. I appreciate the help! Thanks so much.
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Tuesday, September 25th, 2012 AT 5:51 AM
Tiny
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When overfilling occurs, the only thing you would notice is that the recovery tank would overflow but the radiator should not be affected. There should be no air in system, meaning when you remove the radiator cap, it should show full.

How long has this been going on and losing a quart after how much driving time?
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Tuesday, September 25th, 2012 AT 5:59 AM
Tiny
DOMJANSSON
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Minimal driving time. I drive to college. Maybe a 40mile round trip doing 55-60 top speeds. The radiator itself is losing coolant then. It has been doing this for maybe a week. The radiator fluid doesn't have oil and the oil doesn't have water / coolant. I checked both.
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Tuesday, September 25th, 2012 AT 6:03 AM
Tiny
DOMJANSSON
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This is maybe 4x a week. I never go long distances. I used to drive it pretty far but lately its been having issues. It has never redlined or overheated. I always pull over / turn the heat on to cool the engine.
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Tuesday, September 25th, 2012 AT 6:09 AM
Tiny
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Coolant would always leave a trail when leakages occurs and your leak is neither too large nor small so you most probably is not going to see any dripping onto the floor.

Under such circumstances it should be depleting the recovery tank as well but you mentioned it is not. When was the checmical test done?

Did you try bleeding the system to see if there are any changes in symptoms of the coolant loss?
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Tuesday, September 25th, 2012 AT 6:17 AM
Tiny
DOMJANSSON
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I just did it this morning actually because I'm completely baffled. An interesting thing happened actually. I totally forgot about this until now but this is what made me thing it was the thermometer not opening completely. I had drained 3 inches of radiator fluid as the test says. I left the cap off and placed the chemical tester where my radiator cap should be. About a minute into it the radiator fluid started overflowing into the test tube. I assumed the thermometer hadn't opened completely and if this had been happening on the road the fluid would have drained as I drove. I turned my car off, drained an inch more of fluid and reset the tube. I ran my car for two more minutes and it tested clean. (Temperatures were perfectly fine throughout these tests I made sure to monitor them.) Thus the fluid hadn't boiled over.
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Tuesday, September 25th, 2012 AT 6:32 AM
Tiny
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Two days ago I completely bled my system and replaced my coolant completely. I wanted to start fresh and see how much I had lost and it was around a quart in two days.
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Tuesday, September 25th, 2012 AT 6:34 AM
Tiny
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If the thermostat is not opening, the temperature would go up and the coolant would definitely be forced out of the radiator.

If the system is working correctly, under such circumstances, coolant would be forced out to the recovery tank resulting in it overflowing.

The perfect temperature reading recorded indicates it is not the thermostat that is faulty and the overheating would only occur when coolant level drops.

I would still be looking for a leak somewhere.
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Tuesday, September 25th, 2012 AT 6:38 AM
Tiny
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Only other possibility I can think of would be head gasket? I'll still be replacing the thermostat tomorrow just because I have no clue the last time it was done. I figured if it was the head gasket I would have issues like loss of oil, oil in the radiator, water in the oil, ect. My car has none of these and passed a chemical test. I may take it into a dealership and get it diagnosed? I'm not sure where else to check =/
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Tuesday, September 25th, 2012 AT 7:01 AM
Tiny
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For this engine to have a head gasket problem, it would seldom have coolant in engine oil symptoms and vice versa. The chemical test might not be conclusive and you need to have a more thorough test. I would suggest doing the test again and maybe with a different test kit. If you are going to the dealer, it is not going to be of much help with what you have done so far.

Don't make any unnecessary parts replacements yet. I would like you to monitor the situation and in the meantime, bleed the system completely and after ensuring the coolant level in radiator is full and no more air trapped in system, go for a test drive.

Note the recovery tank level and after test drive, allow engine to cool down before rechecking the coolant level, both at radiator and recovery tank.
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Tuesday, September 25th, 2012 AT 7:20 AM
Tiny
DOMJANSSON
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Okay I will do this tomorrow and I'll completely monitor the levels in the recovery tank / radiator. After ill let you know what I find. Thanks again!
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Tuesday, September 25th, 2012 AT 7:36 AM
Tiny
DOMJANSSON
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Bled the lines and DID find air. Did another combustion test and had a friend do a leak down test. Both came back normal and did not find results of head gasket failure. I recently replaced my radiator cap and AUTOZONE sold me an unmarked radiator cap ( didnt specify the PSI) I pressure tested my radiator and its 16 PSI. I then tested the cap and its 13 PSI. Pretty sure I found my problem right there >.>
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Sunday, October 7th, 2012 AT 7:42 AM
Tiny
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The markings should be 1.1 bar for the radiator cap. Lets hope this solves the problem.
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Sunday, October 7th, 2012 AT 8:58 AM
Tiny
DOMJANSSON
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Lets just start over because the cap isn't the problem :(.

There is no dripping whatsoever, no fluid out of the exhaust, and the fans are running perfectly. I installed my own mechanical gauge to ensure the car was in fact overheating. Since then I haven't had my car overheat (two weeks. I haven't added coolant in 600 miles so far.). I check my reservoir every night after work and it's been depleting quickly. After the past 600 miles the reservoir down to the min level and I'm getting worried. I have done a combustion test ( this tests the coolant for carbon deposits / c02 emissions in the coolant. Basically an easy test for a BHG. ) And I also did a pressure test and both didn't come back with any results. After these tests I just went ahead and replaced the thermostat with an OEM thermostat. My car usually runs around 190 degrees and has not exceeded 210 degrees. I noticed something that made me think its a weeping water pump. When I sit at a red light or a few red lights in a row my temp goes up to 205 or 210 degrees but does not exceed this temperature. After I start driving the car cools itself back to 190 degrees.

This sounds like fans but I have tested them and they are perfectly fine. Fans wouldn't explain my coolant loss if the temperature does not exceed 210 degrees the coolant cannot boil out because the temperature is too low.(1.1 bar cap + 50/50 mix). My car runs flawless other than this loss of coolant. Doesn't sound like a BHG when it runs and there were no carbon deposits / c02 gasses in the radiator fluid.

Thanks for reading and I'd appreciate it if anyone could shed light on what I should do / replace next! I have replaced a lot thus far and hope I can pinpoint this soon!

/edit: Also oil is clean and does not contain coolant or water and same goes for the coolant. Coolant is clean and does not contain oil. I have changed my oil within the past week and it was pristine. Also the oil levels are consistent and do not ever decrease. I am very particular on fluid upkeep and keeping an eye on my system.
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Tuesday, November 6th, 2012 AT 6:41 AM
Tiny
KHLOW2008
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You don't have a head gasket problem nor do you have any cooling efficiency problem. The problem is the depleting of the coolant resulting in overheating when coolant is low. Why did you not top up the recovery tank level when it went low?

There definitely a leak somewhere and the leak is very small which would be difficult to detect. Leakdown tests would not show anything as the leak is too small to be noticeable. Check all joints for signs of oxidation due to presence of coolant.
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Tuesday, November 6th, 2012 AT 12:57 PM

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