View Full Version : coolant flow question

07-18-06, 02:59 PM
Ok, I've got a 99 Deville and I'm having a problem with coolant leaking from the coolant tank (through the cap/overflow hose). I know that air and fluid go through the purge line from the water pump to the coolant tank but I was wondering how coolant gets back to the rest of the system. Is it through the same line or is there another line (my car had the engine replaced and there is reason to believe things were changed a bit). Thanks.

07-19-06, 03:12 PM
I believe the return flow line is on the bottom of the tank. It should be visible.

07-19-06, 09:06 PM
Yep, there is a bigger hose, usually 3/4 of an inch in diameter attached to the bottom of the tank. It goes to the engine and the top little tiny hose is an air bleed basically.
If it's leaking out the vent hose then they either overfilled it, you have a bad cap, or something not too good is wrong with your "new" engine.

07-20-06, 06:48 AM
Is it leaking FROM the overflow hose, or near where it actually connects to the surge tank on a little nipple (can I say that here???) just east of the cap? My '99 Deville developed a tiny crack at the nipple which caused a tiny leak when the car was hot, so that after about five months, I'd lost about two cups of coolant there.

Required a new surge tank. Warranty coverage paid about thirty bucks, I had a $100 deductible.

09-16-06, 07:20 AM
I think this is correct thread to tell about some minor problem with my car rather post a new thread .I dare say I am a bit meticulous lol .
As you see in the pictures , coolant flow is what I am experiencing. I was driving yesterday and "check coolant level" came on .However the car was not overheating just sitting dead of the temp gage . Today before taking a trip , I just added some coolant as well as some water .( approximately 2 quarts totally).After that I saw those water around front bumper and near reservoir . I ascribe this to topping up a bit more but I don't think I overfilled the car .
Is this normal that you lose some coolant in hot conditions or not ? We also owned Jaguar VDP but I don't remember we added some coolant or reflushed the system .

09-16-06, 08:51 AM
I admit to being somewhat puzzled by your pictures. Unless the STS engine bay layout is significantly different from the Deville and Eldo, how do you associate coolant loss from the overflow tank (near firewall on passenger side) with what appears to be moisture on the driver's side front end fender/hood line? Or are you thinking it's spraying up from the radiator itself?

What is the subject area of the right-most picture? Your pictures are a bit too close-up for me to make any sense of them.

09-16-06, 09:54 AM
I don't know why my car lost some coolant . The cap is also tight and not a bad cap.What I like to hear is that it's normal you loose some coolant ? Otherwise there is something wrong with the system ?
As to overflowing the radiator , that happens when your car is topped up overtly ,ok . What areas are water sprayed out when you overfill the car ? Just like same areas you saw in the pics or water should drip down on the ground .

09-16-06, 08:17 PM
No, it is not normal to loose coolant unless you over filled the tank. Coolant in the area you have pictured is not from the tank. It appears to be from a radiator hose or the radiator itself. Remove the shroud that is wet in the bottom picture and you should be able to see where it is coming from.

09-17-06, 09:48 AM
Thanks Ranger .
I will take a look at it .