Baffled by coolant loss

[mwntrolley]

Hi Folks,

First, thanks for all the great posts. They have been extremely helpful to me.

I am baffled by an unexplained loss of coolant. I have a 2000 SL2, 1.9L DOHC. The low coolant light comes on after cold starting about once every 10 days (I drive the car typically 400 miles/week) and I have to top off the coolant resevoir.

I changed the coolant and hoses about 6 weeks ago after this warning came on for what was then the second time since most of the hoses looked pretty worn. I replaced every hose except for the hose to the transmission cooler, which looks almost impossible to get to.

However, this problem hasn't gone away, in fact it has gotten worse. I have checked the following:

1. I parked the car in the garage for several hours over some towels. No leaks were found on the ground under any part of the engine.

2. There is no anti-freeze in the oil, either on the oil cap or the dipstick, so I am assuming the head gasket is fine.

3. I drained the block when I changed the coolant 6 weeks ago and did not strip the threads on the block drain plug.

4. I read Wolfman's discussion on the ECTS, but found no leaks there, either.

Any ideas? If coolant was leaking onto the transmission, could it be evaporating off? Has anyone replaced this rear hose and know an easy method?

Thanks for any help.

- Matt Nawn

[Razorbak]

Could be any number of things. Have you checked the coolant surge tank itself for leaks down around the bottom? (You have to remove the bolt that holds it in place and then lift up the unit and examine it.) How about around the water pump flange? Have you replaced the cap on the tank? Look carefully down along the passenger's side of the engine bay and see if you notice any visible trail of coolant. Also check the radiator petcock for potential leaks. You might only be loosing coolant while you're driving at speed, which might explain why you don't seen any pools developing beneath the car when parked.

[geartooth94]

my cooling system was loosing coolant only when the car got up to normal operating temperature. It turned out to be a loose hose clamp at the lower radiator hose.

if you used the screw-type band clamps then tighten them up.

[eRic 02sc2]

one time in band camp... oops wrong story. anyhow the last time my sc2 lost coolant it from a faulty cap on the coolant surge tank. what would happen is the coolant would get up to temp then "boil over" through the cap that wasn't holding the pressure. I saw what was happening when I was running the car with the hood up and letting it get warm. i replaced the cap and it's been fine ever since.

[ssicarman]

If you have never had the intake manifold replaced on the engine check it. Providing that you have the black plastic intake which you should on the 2000.
Check the back of the engine/manifold area where one of the heater hoses and the small hose to the surge tank is. You are looking for dried coolant there and trailing down from that area. If there is coolant there then you need to get the intake manifold gasket replaced. Saturn has an updated one that will repair the leak.