blanning

Hi Everyone. I have a 2005 1-ton express van, the 15 passenger model. It has about 80k miles on it. It's developed a sometimes coolant leak. I can fill the reservoir, start the van, and let it idle for a half hour and no leak. The other day, I decided it might be RPM related, so I wedged a clamp between the seat and the gas pedal to get the RPMs up. I did that for about 20 minutes... no leak.

Then we drive it for maybe 30 or 45 minutes, when we come back, the reservoir is empty. The leak is somewhere high in the engine because it never completely runs out. We get the problem where the heater cuts in and out because there's not enough coolant to go around. When you get out after that, the front of the van smells like coolant.

If I had to guess, I'd say a heater hose running back to the heater core is leaking and spraying onto the exhaust manifold. But it's just a guess. I've never seen any steam. Of course, visibility is terrible because it's all the way up under the dash board.

I have a compression tester, but the adapters that came with it don't fit my radiator. And anyway, the 20 minute rev test should have showed the leak.

Can anyone suggest something to test or a way to flush out the problem?

thanks.

brian

EnyChevyUK

My 98 Express suffers in the same way. When the engine is warm there is no sign of a leak but returning after the van has been stood for a while shows a small amount of coolant on the floor.
I have now discovered that coolant is escaping (very small trickle) from the radiator cap (pretty simple but hard to detect) and on the opposite side to the cap on the inward facing section of the rad there is what looks like a large nut type blanking plug which has also has coolant escaping from it.
I only detected these minor leaks by looking around after the van had been stood overnight and not started up.

wogden

I have seen the engines with the plastic intake manifold begin to leak after age catches up with them. Have to find out if is internal or external. I would think that you would see some residue if it was an external leak. Internal a little trickier. Nothing in the oil? Plugs show anything? Just a few thoughts. Walt