Losing coolant

[Dadillac]

My daughters '98 SL2 is losing coolant at the rate of about a half a quart a week. After several searches I figured it probably was the water pump. I got under the car today and had it running for about an hour. I cannot find any leaks anywhere even after revving. I checked the exhaust and it doesn't seem to be blowing any coolant. One thing that I saw was the "overflow" hose from the coolant reservoir runs along the firewall and goes into the throttle body. That seems weird as I have never seen a car set up like that. Both upper and lower hoses are hot when the engine is at temperature. The temp gauge gets to 12 o'clock and the fan kicks on. It isn't idling rough or anything. Any ideas? Also is the DOHC engine more likely to leak coolant while warm and pressurized or during cool down? Or maybe when it is cold? This one is driving me crazy

Don

[fdryer]

Try removing the serpentine belt and rock the water pump pulley to feel for worn bearings. Another leak area is the upper transmission line going into the radiator. Cracking around the fitting/side tank or anywhere on either side tank as plastic ages and gives. Coolant stains leaves a dry pasty coating. Old hoses and loose clamps makes up the rest of the possibilities. A blown head gasket is a whole different ball game.

The best test would be to find a loaner tool; a pressure tester with an adapter to fit on the reservoir so you can pump up to 15 or 18 psi of pressure on a cold system to search for leaks. A home made pressure tester with a hand pump, pressure gauge, and spare reservoir cap with a tire valve would work too.

[hoseppi]

Don, that's not your overflow-it's part of the pressurized side of the cooling system. As far as the missing coolant, it may be coming out of the radiator from a crack that usually develops on these models, just under the inlet hose(that's the upper hose,drivers side).

[Dadillac]

I checked the radiator out like I was a scientist looking for a germ. No radiator leaks. This is what confuses me. No leaks but losing coolant. No smoking exhaust and no milky oil.

Don

[Dadillac]

Well I found the leak. The driver side tank is leaking where it mates to the core. I am just gonna buy a new radiator. But I remember that I had major issues with the trans lines. To save me from doing a search does anyone know where I can buy the trans lines?

Don

[hoseppi]

I know, that bottom one likes to rust solid. Sounds like you may have replaced at least one already anyway, so maybe it won't be so bad. If not, you can take the lines loose at the transmission, pull the radiator and remove the lines once you get the radiator on the bench.

[Dadillac]

Well when I replaced the radiator after buying the car about a year and a half ago one of the trans lines just would not come out of the old radiator. I had to use vise grips and really messed up the fitting. I ordered new ones from Saturn parts dot net. I am positive that the old ones will not be serviceable anymore. So I ordered a Sherman radiator from Rock Auto and the trans lines. Hopefully they get here by next Saturday. Oh and the radiator only leaks when the temperature is cold. I checked it out on Friday for an hour while the engine was running and hot. Revved the engine quite often too. Not a drop anywhere. Left cardboard under the car until Saturday morning and not a drop fell. As soon as I topped off the reservoir it started dripping from the driver side near the lower trans cooler fitting. But it is leaking where the side tank mates to the core.

Don

[magreger]

I had the same issue with my trans lines. I mangled the heck out of them trying to get the off. I managed to get them screwed back onto the new radiator, but I don't see them ever being used again.

Judging by your posts you have two leaks? The core and the radiator?

[RobertGary1]

Most coolant leaks seem to be very temp sensitive. Its not unusual for it to not leak continuously. With the engine off put your finger around the back of the water pump pulley. If you feel any wetness, the pump should come off. It should be bone dry. Also look around the water pump below the pump (you probably need to remove the right wheel and splash guard to get a good view. If you see any wetness, replace the water pump. 95% chance its either the water pump or the side tank on the radiator about 2" below the top hose.

If you really believe there is no external leak (never see coolant in the parking lot, etc) you could check for burning coolant. The test is simple. With the car warm bring each cylinder to TOD and apply about 100psi pressure to each spark hole. Remove the reservoir cap and look for any bubbles. If you get bubbles, that cylinder is burning coolant.


-Robert

Originally Posted by Dadillac

My daughters '98 SL2 is losing coolant at the rate of about a half a quart a week. After several searches I figured it probably was the water pump. I got under the car today and had it running for about an hour. I cannot find any leaks anywhere even after revving. I checked the exhaust and it doesn't seem to be blowing any coolant. One thing that I saw was the "overflow" hose from the coolant reservoir runs along the firewall and goes into the throttle body. That seems weird as I have never seen a car set up like that. Both upper and lower hoses are hot when the engine is at temperature. The temp gauge gets to 12 o'clock and the fan kicks on. It isn't idling rough or anything. Any ideas? Also is the DOHC engine more likely to leak coolant while warm and pressurized or during cool down? Or maybe when it is cold? This one is driving me crazy

Don

[Dadillac]

The car is repaired. I took my time and got everything just right. No more leaks. I inspected the old radiator and found no cracks. So I guess it was coming from where the side tank meets the core. The toughest part of the job was removing the clips, that hold the trans line into the trans, and putting them on the new lines. Seems pretty stupid that I get a new trans line with everything I need except the plastic clips. What the hell is up with that? But I digress

Don