Losing coolant

[adavery]

I have a 1995 SHO that is losing coolant. From where I do not know. There are no drips or puddles on the ground. There are no visible wet or damp spots on the enging or the engine compartment. Over the last month or so I have driven approximately 100 miles and have had to add 1 gallon of coolant. This was spaced over 7 or 8 incidents of adding coolant but the total was 1 gallon added as I just finished off the gallon last night. I am using a 50/50 mixture. Although there are no leaks visible anywhere after driving 5 -10 miles at speeds 35 to 70 when you stop and get out of the car you can 'smell coolant around the front of the car'. The temp gage(factory) usually rides around the M in NORMAL. However, lately (since I have started losing coolant) the gage will soar above the N but not above the line just short of HOT. If you de-cellerate, not using the brakes but just let the engine wind down, the temp goes up a little. If you engage the clutch and rev the engine the temp goes down some and if you accellerate the temp seems to go down some or at least stabilizes. The fluxuation (up and down) on the temp gage from around the M in NORMAL to the line just above the N (almost to HOT) is fairly rapid after driving 5 - 10 miles. This fluxuation doesn't start until once the gage has gotten to it's highest temp reading then the varing readings start. I know factory gages are notoriously inaccurate and I am not worried so much about the gage movement as I am about the loss of coolant...that's not a factory defect or gage shortcoming. I believe what my gage is telling me is pretty accurate because it was accurate last year when I was having cooling problem and we had it hooked up to a computer checking the temperature that the thermostat was opening and closing, also when the fan was coming on and going off. Any suggestions appreciated.
Thanks,
adavery

 

[Mr Anonymous]

Sounds like you may have a pinhole leak somewhere that is hitting a hot engine component and burning off rather than resulting in a puddle. Best bet would be to perform a pressure test to see if you can find the leak. Alternatively, you could get a bright flashlight and look for steam while the car is running and see if you can find it that way.

 

[adavery]

Thanks. I'll give the pressure check a try. I have already done the flashlight while the car is running search. Nothing visible.
adavery

 

[morpho18]

check your throttle body coolant lines. I did the throttle body coolant bypass, and my coolant leaks went bye bye.

 

[oh_SHO]

I was having the same problem without the temp fluxuations. Finally my raditor split open and left a puddle. Before the puddle I never saw any coolant. Sounds like the t-stat could used to be replaced once you fix the leak.

 

[adavery]

No leak there. That is the spot I use to bleed cooling system of air since it is the highest point the coolant travels.
adavery

 

[adavery]

Radiator and tstat less than 2k miles old. I know that doesn't mean they are good but it is an indication that they are PROBABLY good. If the radiator has a problem it show on pressure check. I will test tstat at the same time.
thanks,
adavery

 

[adavery]

I found the coolant leak. It was the heater hose between the engine and the firewall. Thanks for everyones suggestions.
Adavery

 

[Jrodm12]

ahh that should be no problem to fix i had problems with my heater hose also and in turn it also cut one of my tb coolant lines cause of all the heat. Is the heater hose still good or just gunna replace whole thing?

 

[adavery]

The heater hose has a metal end formed on it. I may be able to cut it down and put another hose on the end of it with 2 hose clamps (one on the engine block and one on the reformed end of the heater hose). If that doesn't look like it will work I will have to get a completely new one.