Coolant steam out of the tank cap

[phiebert]

I've been smelling coolant when parking my 94 RT for a few weeks now. Yesterday I let it sit and idle until it got really warm. Expecting the worst I looked for gasket leaks, water pump leaks, etc. It turned out that the coolant smell was coming from steam coming out of the cap on the coolant tank.

I ran out and bought a new cap but that didn't help. It doesn't do it until the car is warm enough for the fan to come on and even then it isn't much. But I assume under normal conditions it shouldn't do that...or should it?

The tank isn't broken, the cap is new (16 lbs) and the coolant is clean and the engine doesn't seem to get warmer than it should according to the gauge.

Any ideas? Has anyone ever noticed this before on their car? Would it make sense to put on a higher poundage cap?

 

[HP]

Could be bad head gasket allowing compression from cylinder to leak into
water port. If that's the case - you're probably getting coolant into
the cylinder also. Pull your spark plugs to see if any are fouled or have signs of coolant contamination.

 

[joe117]

I think you can check the coolant fumes with an emissions probe. If there are signs of exhaust gas in the coolant then you probably have head gasket leaks. I've never done this but I think it is SOP these days.

 

[Snake Bitten]

I think HP has nailed it...unfortunately...

You could simply change the rad cap, to see if the cap is bad...you shouldn't go with a higher psi cap, as it is designed to be the safety valve, so you don't rupture the rad itself...

You can put a pressure gauge on the rad in place of the cap....idle the car, give a few blips of the throttle, and see if your pressure rises with the throttle...Dead giveaway that cylinder pressure is leaking by....

A great way to check if cylinder pressure (which is greater than the rad pressure) is leaking by the head gasket is to do a leak down test....Similiar to a compression check...Pull your plugs one at a time, put air pressure on each cylinder, one at a time, and with the cap off the rad, you should see bubbles on the cylinder(s) that are leaking by...

Once this condition gets bad enough, very minor blips of the throttle will push all of your coolant out the rad, into the overflow, and then onto the pavement...

Cheapest quickest test is to simply buy a new OEM cap...Let us know how you make out...

 

[Steve-Indy]

You can also send a crankcase oil sample to a qualified lab for analysis...tell them that you are worried about coolant leak thru head gasket. (I use Blackstone Labs in Fort Wayne,IN)

Good luck, and please keep us informed.

 

[Geoff Green]

If the over flow hose between your radiator and the overflow tank is clogged it will cause coolant to come out of the radiator cap.

 

[95Viper]

Take off your radiator cap. Is the tank full? If not fill it and burp the car. Air in the system heats up and forces fluid out of the system. This should just push fluid into the overflow tank but also take off the hose at the radiator cap and blow through it just to see if it bubbles in the overflow tank.

Also, check the overflow tank when cold. Is it full? Empty? Turn the wheels to the left, take out the rubber round "thing" in the fenderwell. Stick a flashlight in there and the tank fluid will glow. **** out or fill to bottom mark. Blowing through the tube to it will tell you if it's blocked.

I went to the Blackstone website $20. I'm sending in a sample for the heck of it.

 

[phiebert]

My rad cap is new, my overflow hose is clear...someone please tell me there is another possible problem besides head gasket.

Is it possible to do a noticeable leak down test on a Viper because there is no Rad cap. Will it bubble out the plastic tank?

OK, this is probably a sin to ask, but what about "stop leak" products? If it stops the leak into the cylinder great, as long as it doesn't plug up anything else. A guy I know had a Ferrari with a head gasket leak and he swore by the stop leak stuff. Said it fixed the problem pretty much permanently (versus a $20K bill on a Testarossa for changing the gasket!).

 

[Tom Welch]

Patrick,

Unfortunately, Gen 1 cars have a history of "seaping" coolant and head gasket issues. The good news is that there are new head gaskets available from Mopar. Expect 900 to 1200 in parts and labor for the gasket exchange including labor. I'm sure that there are a few folks who can chime in with their experiences with the same issue as yours.

A couple of questions;

1. What color is the water..and does it look like a chocolate milkshake and foamy?

2. What does the oil look like on the dipstick?

Tom

 

[joe117]

Take it to a shop that has a tailpipe emissions probe. If there are combustion products in the steam then it is the head gasket. This is SOP for most modern shops. It is a sure thing test.

 

[95Viper]

Did you fill the tank and burp the car? Assuming you checked the overflow tank and it is at the low mark when cool, does it move up as the car heats up?

Follow the burping instructions on the "how to" section. and report back. I like Joe's suggestion about the emissions probe. Do that too after burping. Also, sign on to the Blackstone website and have the test kit shipped to you, it's take a few days.

 

[phiebert]

Patrick,

Unfortunately, Gen 1 cars have a history of "seaping" coolant and head gasket issues.
A couple of questions;

1. What color is the water..and does it look like a chocolate milkshake and foamy?

2. What does the oil look like on the dipstick?

Tom

Tom, the coolant looks pretty good. A nice green (mix of coolant and water) and not foamy. The oil looks pretty good too, although I've had a recent oil change. I'm still planning on changing the head gasket but now I'm wondering if that is the problem. Any other thoughts?