: keep losing coolant...hard to trace



noobie
09-18-06, 02:57 PM
I have an 1999 Cadillac STS and I have trouble with the coolant loss. I have to fill my coolant in a week and a half or 2. I couldn't find any leaks, very hard to trace.

Can anyone suggest on how to diagnose the problem? Thanks.

Ranger
09-18-06, 04:17 PM
If there are no signs of coolant loss, do a cylinder pressure test to condem or rule out the head gaskets.

bill6ft6
09-19-06, 07:31 AM
Very likely "headgasket" situation. Ranger is right, but quicker, but not quite as accurate method is to look in the coolant expansion tank for bubbles or have it sniffed for carbon monoxide. As for it being hard to find leak, at spped or RPM combustion pressure will get into the coolant passages and overpressurize the cooling system causing it to blow out the overflow at the expansion tank.
Personal suggestion.... sell it now, it will get worse
wrt

Reactor
09-19-06, 10:07 AM
Have you tested the radiator cap, they go bad frequenty, you would loose water the whole time the car is running and when you check the level, (car off and cold), there seem to be no leak and the level is low.
I have found that even new caps are bad, I check them before I leave the store to make sure I have a good one.

Blown Z
09-19-06, 11:10 AM
Is "milkshake" looking oil on the dipstick with a car using Dexcool still a good indicator of a blown head gasket?

Ranger
09-19-06, 11:14 AM
Yes, but not on a Northstar. Our old Guru always said that the Northstar will rarely put coolant in the oil when a head gasket goes. I forget exactly why, something to do with the design.

Blown Z
09-19-06, 11:40 AM
Thanks for the reply Ranger! I am losing coolant but I can see where it leaks on the ground. It doesn't overheat at all or anything so I'm suspecting a bad cap or leak in the radiator. I see you're in Woodstock? We oughtta do lunch sometime!

Ranger
09-19-06, 12:56 PM
Where are you?

Blown Z
09-19-06, 02:44 PM
Where are you?

I am in Hinsdale and in Sterling, IL. I travel between the two places often for work. I call I-88 my second home, lol! If I remember correctly, Woodstock is North on 47 from 88?

ewill3rd
09-19-06, 03:30 PM
Probably the coolant crossover seals.
Is the leak on the ground about a foot inboard of the left front tire and almost in the same spot?
If so it's either the bypass hose off the back of the intake (or the fitting) or the seals on the coolant crossover.

If it's more towards the front it could be the cover or the pump, but I am assuming that it's "harder" to spot than that.

Ranger
09-19-06, 04:14 PM
I am in Hinsdale and in Sterling, IL. I travel between the two places often for work. I call I-88 my second home, lol! If I remember correctly, Woodstock is North on 47 from 88?
Correct.

noobie
09-20-06, 12:24 AM
I'll check the cap and the pipes on the overflow tank, head gasket will be last. I hope it's not something major that I need to sell the car. :D

Also, you always mix Dexcool coolant with water right, 50/50 ratio?

Ranger
09-20-06, 10:55 AM
I'll check the cap and the pipes on the overflow tank, head gasket will be last. I hope it's not something major that I need to sell the car. :D

Also, you always mix Dexcool coolant with water right, 50/50 ratio?
Yes.

HerSTS
11-18-06, 07:01 PM
Our 2000 STS is also leaking. According to the estimate I got from our local dealer, the coolant is leaking from the coolant crossover and it would cost about $1100 to fix but since they'd already have the engine/trans down for the dreaded P0741/P1860 fix they'd do it for $500. What exactly is entailed in fixing the crossover leak? Is it just seals and hard to reach?

Thx - Dan

Ranger
11-18-06, 07:44 PM
Yup. If you look at the engine from the drivers fender, you can see the crossover running from one head to the other under the TB. It is a lot of work to R & R the gaskets. Just had mine done, but it was a warranty job so I don't know what the bill was. They did keep the car for a day and gave me a loaner.