After replacing the hoses we topped of the coolant resevoir. Too much!! After a day of city driving I noticed my engine temp, normally at 210 approaching 220. I pulled into my garage and turned off the motor. Splash!!! All hell broke loose. I opened the hood and noticed that the coolant resevoir was spilling coolant from under the cap and the cap was sitting and a slight angle. Apparently the pressure just popped it up a bit. I waited for the motor to cool down. Replaced the lost coolant (to the "fill to here" line) and tightened the cap back down.

A few days later I was again caught in traffic for awhile, notice my temp closing in on 220 and continued to run my errands with no problem. I got home, parked it and went inside my house. I came out later in the day and noticed coolant on the garage floor again. Not nearly as much but still a good sized puddle. The resevoir was emptied halfway from the "line" to the empty mark. I again refilled the resevoir to the "line".

Monday SAME THING HAPPENED!! I can not find a leak. All clamps are tight. It seems to be releasing fluid close to the radiator. I started the car the other night and just let it run to get the temps up. I could not get it to go over the 210 mark. After shutting her down I waited for the event ... nothing happened.

We are going to check the pressure on Friday. Anybody have any ideas. I do not want to take it out and run the risk of getting stuck.

 

If the coollant is coming out of the overflow bottle I don't think you have a leak. I think you just over filled it.

When you drive and shut down, the engine continues to heat up because the coollant is no longer being cooled. Because of additional heat cycle the coollant expands. This is what the overflow tank is for to collect the expanded coollant until the engine cools down. If you over fill, the coollant should flow out of the overflow line from the overflow tank. I guess you put so much in that the pressure overwhelmed the ability of the overflow line to handle the volumn and it blow the lid of the the tank.

I say don't worry about it, it should stop overflowing once it has reach the proper level.

PS> You should only fill the overflow tank to the full line when the engine is cold, not when hot! This is probably the source of the problem.

 

I have filled it to the full line twice now while the motor was cold. I have noticed no movement in the level of the fluid. There is no drip, drip it just pours out from somewhere and I can not seem to catch it in the act. :confused:

 

Oh I misunderstood. Any time I've had such a leak (after shut down) it's been from the Water Pump?

Try parking over dirt so the coolant won't spreadout so much, maybe you can find the location that way? Good luck!

 

The symptoms you describe point to a defective radiator cap.
Water normal boils at 220 degree F when under normal atmospheric pressure but starts boiling at 250 degree F when under 15 psi overpressure.
Don't know where the cap is. Maybe under the radiator shroud?

Hope this helps.

Roger

 

I agree I would place cardboard under the car and check it every 20 min, or until you can determine where the leak is coming from....

Also take it to the dealer and have them do a pressure check on the coolant system...

I would hope that your not leaking out of the head gasket.... Its possible...

Just be happy that you have dropped a sleeve.. Theres a black vette (Calvins) from Baltimore, MD, that dropped a couple sleeves and MTI said that there not going to warrenty it... And he never sprayed N20.......

Good luck with yours..

X

 

We are doing a pressure check today. I do not think it is anything seruous. It doesn't leak per se'. It just simply dumps some after I stop the car. :confused:

 

NoMercy,

You may have and air pocket in the system. Don't know about the C5, but in some cars it can be pretty hard to get them worked out of the system....takes time.

Good luck.
Mark

 

I woke up in the middle of the night thinking the same thing (air pocket). That would explain running a bit warmer, and the excess overflow after shut down (because air expands much more than coolant when heat increases). Again, good luck!

 

First of all, C5's dont get air pockets in the system like most cars because the reservoir tank is pressurized and it is the highest point in the cooling system. The "radiator cap" is actually the cap on the reservoir tank. I would replace it and go from there.

Eric

 

Could be a bad thermostat or your water pump going out too.

 

Had the same thing happen, I just had to much coolant! Hey Bill u in Colorado yet?? Thats not to far from me, I gotta see that thing run!! :D

 

No Mercy,

In my 97 C5 I had the same problem. You know what they finally determined it to be? The head gaskets were leaking. Pressure from inside the pistions was making it past the headgaskets and into the coolant sleeves. This would cause the coolant to overflow from the coolant reservoir.

 

Anytime you drain your cooling system on a C5 you have to burp it. What you do is get the car to operating temp with the cap opened slightly. then rev engine to 2000 rpm for about a minute. This should get the air out of the system. Once with this is done then you fill it to proper level in resevoir. :U

 

Pressure check was done and guess what ... there were a few loose hose clamps. :lol: :lol: :lol:

Sytem was retested and the car was driven and no leaks, temps are fine and life is good!! :D

Thanks!! :cheers:

 

:cheers: Good news! :cheers: