Mystery bubbles in coolent

[shaner]

Hi all, i am trying to solve a problem and i am stumped.....

My van started to blow coolant onto the ground from the overflow tank after I stopped driving. I noticed that the tube into the coolant overflow reservoir is making bubbles. I assumed the worse (gasket or new head)and brought the van into a mechanic in Edmonton. After a month of waiting for the jerk to start working on my van i brought it to a different shop. These guys did the carbon monoxide test to the coolant and it came back negative. They figured it was just the rad cap, lucky me I happened to have a spare. I got them to fix up a few other things and I was really excited to have my van back. By the time I got it back to Camrose however I parked it and noticed coolant on the ground...... I started it backup and noticed a ton of bubbles from the overflow tube into the overflow reservoir.....

Any ideas? I am going to try and find a coolant test kit in Camrose tomorrow and redo it. Maybe they messed it up

[FalcoColumbarius]

Check out your oil cap, see if there are any white spots under the cap. Usually, as I understand it, bubbles in the radiator overflow is kinda like bubbles in the bath ~ a back flow of compression leaking through a small crack, hopefully in your gasket and not your head. Having said that, it could be an air leak, which would be a much better scenario to deal with. Even though you've changed the rad cap, to make certain that it is not scored, check the seal ~ a small hairline crack and it's no good. The cap has to be matched to the system, if the spring is too light then the system will prematurely spill out. You can check the cap with the cooling manual in the L300 Dedicated Category Reference Forum. Out of curiosity, are you overheating at all? When was the last time you you changed your coolant out? What do you know about your thermostat? What coolant are you using?

Also, just so you know ~ I'm not a mechanic, just a Starwagon hobbyist.

Falco.

[shaner]

I was not overheating. My temp would rise and lower a bit but it never went crazy. I attributed this to a faulty fan clutch which i have since replaced. I just did a ph test myself and from what I can read it seems to between 7.5 and 8. Which to my understanding is bad. My new cap came from CVI so I would assume it is the right one. The old one was definitely faulty since the mechanic pressure tested it. Also there is no oil in the coolant and no coolant in the oil.

Thanks for the tips.

[FalcoColumbarius]

Keep your old fan clutch, eh? There are youtube vids on how to replenish the oil in the viscous clutch. I replaced mine and tossed the old one before I discovered this vid.

Falco.

[glenn]

Unfortunately, the symptoms are consistent with a cracked head. My van showed none of the usual tell tale symptoms (oil in coolant, coolant in oil, white smoke, etc) except for the over pressurized cooling system. The longer you drive, the more it pressurizes and it eventually starts dumping coolant via the overflow bottle.

Run your van with the radiator cap loosened for a while, you should see less or no loss of coolant. And watch your temperature, don't push it at all now that you are running your cooling system without pressure.

I think this is an idiosyncrasy of the way these heads crack - they always seem to crack in the same place. It doesn't permit the exchange of fluids, but it does allow pressure from the cylinders into the cooling system.

Good luck!