Coolant coming out of the radiator cap!!
 

I'm once again turning to you guys here on the forum for some advice. I had to drain some coolant out of the radiator (aluminum)to have a small pinhole leak repaired, I guess it was from a small rock.

After the leak was fixed, I filled it up with coolant by adding coolant through the filler neck until I could see it. Then I started the car with the cap off & when the thermostat opened & I could see the flow, I topped it off to the bottom of the filler neck. I then put the cap on & filled the overflow bottle about 1/3 of the way up. This worked good the very first time I did it.

The car was okay idling but when I would drive it would run a little hot. So I decided to bleed it again. This time, after the thermostat opened I would see coolant flow nicely then all at once I'd get a big "tidal wave" of fluid puking out. It would then go back to a steady stream & then the tidal wave hit again.

Out of frustration I just put the cap back on & called it a day. Today I let it warm up, drove it for maybe 10 minutes & it puked coolant out from the radiator cap. It's a brand new 13 lb. cap. The engine is a basically stock 289 & I never had any problems like this before. I alwaays ran a 13 lb. cap & had no problems at all.

I'm thinking there's some air pockets in it, am I on the right track??

Thanks!

1) How hot did it get before you fixed the pin hole?

2) You probably still have a bunch of air in the system.
Jack the front up as high as you can get it (put it on jack stands). Then purge the system again. This time keep filling it up until it quits pushing the coolant out (do not fill the overflow at this time). Wait until it cools down and then fill the overflow only about 1/4 to 1/3 full. Drive it then and see how it does.

Watch the overflow after a couple of drives and be sure that it is not completely empty after it cools off. You want a little bit left in the overflow so you can see at a glance if it is using coolant.

At least that is how I do it.

Terry,

1. Before the pinhole leak was fixed it got to about 200. I know thats not really hot & a far way from overheating but my little 289 usually stays right around 180 cruising down the road even on a 100 degree day.

2. So, I'll jack the front end up, start it up & let it keep pushing the fluid out while I add fluid to it, sounds a little messy but I'll do it.

Thanks for the help, wish me luck!

Randy

You say it is pushing coolant out around the radiator cap. Is it not sending it to the recovery tank?
If the upper gasket on the cap or its corresponding surface on the radiator neck is damaged it will leak around the cap and it won't draw back from the recovery tank when it cools off.
You may also want to check the hose to the bottom of the recovery tank to make sure the radiator can push fluid through it. It's also possible the vent for the recovery tank is not functioning. The top of the recovery tank should be freely vented to the atmosphere.

Keep us posted on what you find.

Yep, it's pushing coolant out from beneath the cap. There's no damage on the filler neck and the cap is brand new. At first I thought the old cap was bad so I installed a new one after work today & it's doing the same thing.

The vent on the overflow bottle is clear. Some fluid is getting into the overflow bottle but it "gushes" so much fluid through the radiator hose all at once, I figure the small diameter hose can't keep up with it. So what doesn't make it down the hose to the overflow bottle, comes out from beneath the cap. Must be a lot of pressure! Thats why I think it's air in the system.

I'll let you guys know what I find out.

Thanks!

Are you sure the radiator cap is on tight. I don't know about yours but I think mine is a two clicker. Put it on and turn it until it stops and then push down and turn it about 1/8-1/4 turn more.

Just a quick thought here....does your lower hose have the wire coil inside it to keep it from collapsing? If not, it could collapse and there won't be adequate flow to the engine, the little coolant that does make it will heat rapidly, then surge.......

Cheers from Dugly :cool:

No, the lower hose doesn't have a coil in it. Can I tell by looking at it while the car is running if it is collapsing?

Thats an interesting thought.

Thanks.

One thing I forgot to mention. Saturday was the first day I had the car on the road since bleeding the coolant system. I drove to a car show that morning, temp outside was about 70 & the show was 25 miles from home. The car was fine going to the show, no leaks. Coming home with the air temp at about 95 is when it started leaking out the cap.

Don't know if this info helps, just thought I needed to include it.

Thanks.

Here's the best solution to adding fluid to the coolant system and ensuring all air is removed. Here's a link where I discribed it.

http://www.uniquecobra.com/forums/forumdisplay.php?f=68 then click on the Engine & Cooling thread, then scroll down a few posts to Airlift coolant system

Mark

Yes, just squeeze the hose..... if you have a metal coil in it, you'll feel it and will prevent you from collapsing the hose.

Mark

If the hose is collapsing, you should be able to watch it collapse while revving the motor sitting in the driveway (the water pump suction is what sucks it to a collapsed condition).

I'm also betting on air in the system though.

Thats worth a shot too, I'll check tonight.

Thats another thing I'll check tonight. Would a lot of air cause the hose to collapse or would it be simply a bad hose?

Thanks everyone, the advice is great!

Randy

Now that looks like an easy way to bleed the system! Just not sure if I have the extra money to put into it right now.:(

It's fixed!!:)

It turns out there was air in the system like you guys said. But........

Terry wins bragging rights because as he suggested, I didn't have the radiator cap on all the way.:o :o

The reason I got the "tidal wave" of fluid the other day when I was trying to bleed it was because I drove it with the cap not on all the way on & it sucked in a LOT of air. The car ran so cool going to the show Saturday morning (65-70 outside) it didn't even spit any out. But on the way home when it was 95 outside, then it leaked out from the cap.

Tonight, I filled it through the manifold, then filled the radiator, started it up, left the cap off, once the thermostat opened I saw a nice steady stream of coolant along with air bubbles. Once the bubbles stopped & the flow was nice & steady, I closed it back up. Took it out for a quick spin, temp stayed at 180 -185. Now after the car was sitting for a little while it sucked a little back out of the bottle & all appears to be good.

I can not believe I didn't have the cap on all the way. I've been working on cars for 30 years & that never happened to me. I must be getting old.;)

Once again, thanks to all, I knew I could count on the good folks here on the forum.

Randy

As I was reading through two things occurred to me: Cap loose, especially easy to do with the in-line cap, or debris under the gasket. That happened to me - I put some silver seal to plug a small leak (yep, rocks) and some of the flecks stayed. It overflowed later that day.

Its the simple things that get you every time...........

I'm glad to hear that I'm not the only one that something like this has happened to, guess I'm in good company!;)

Brothers by another mother..........