Coolant light on them off as engine temp changes ?

[bru023]

When engine is cool the light goes on.... as the auxsix fans kick in it turns off..

I can't find any leaks but it is loosing some coolant.
I checked both tran oil and oil no coolant mixing.

I'm baffled help.

Plus the heat blows cold at idle and heats up as I drive.
Getting tired of this car

[Diseasel300]

Coolant expands as it heats up. If you're marginal on the level in the expansion tank, it makes sense that the light would be on when cold, but go off as the engine heats and coolant expands and the level in the tank rises to raise the float. Fill the expansion tank and see if it still does it. Also find your coolant leak. It may be related to the next point...

Poor heat at idle that increases when the engine is revved or the vehicle is under way can point to a failed/seized auxiliary coolant pump located near the monovalve (or duo valve on some cars). Its sole purpose is to circulate coolant through the heater core to improve heating at idle and low speeds. You may find your shaft seal failed on the pump which can also be your source of coolant leak (Just went through that myself).

[Mxfrank]

There a few places where a coolant leak would be unnoticed.

- Check that the header tank neck isn't loose in the plastic casting.

- Could be leaking from the heater core or hot water valve

- And if it just can't be found elsewhere, suspect a leaky head gasket.

[bru023]

I just brought it up to temp drove it. Shifty fine but it's leaking a lot of coolant from the transmission. / middle under the car.
Transmission
I cant see any leak from above but under the middle of the car it's dripping out fast only when it's warmed up. It seems like or looks like the leak is from the trans oil pan but it's also leaking onto the front tie rods ....I'm lost

[Diseasel300]

The transmission has no coolant running through it. There is a heat exchanger inside the radiator for the transmission oil. If you have coolant in the transmission, you have bigger problems.

Most likely you have a failed head gasket causing coolant to drip down the back of the engine, OR you have a failed heater core causing coolant to drip out the HVAC drain which will puddle under the transmission.

[Diseasel300]

Not as familiar with the 124 as the 126, but if you have the "false firewall" it is possible that you could also have a failed heater hose, Aux pump, or monovalve leaking coolant. If so, it'll drip down on top of the transmission and could certainly end up near the steering components.

[bru023]

Solved so far . The heater hose attached to rear of engine had a hole.... I squeezed it and it spit out coolant phew, thought it was freeze plug or worse....

I used tap water to get it home , should I flush it and put distilled water and coolant asap?

When I took off the hose it was rotting on the inside I did a quick fix and cut the part that had a hole it was close to the clamp and reclamped it a pain in the ass to reach had to use small monkey wrench.

Got to order new hose plus this plastic piece it goes to also the plastic was broke in the hose.... whole car is falling apart. Love her but might have to let it go.

Thanks for the help

[Diseasel300]

Well that would certainly do it. If your tap water isn't hard (lots of minerals) don't worry too hard about it. If the engine is due for a coolant service (every 5 years minimum) use it as an excuse to do so.

23 year old cars are going to require upkeep and maintenance. Part of life unfortunately.

[bru023]

I did the coolant when my engine block freeze plug rusted out and blew leaking out all the coolant .. added k seal and put new freeze plug and used red thread sealant because it still leaked. By far the hardest repair I've done