Hi,
I need your suggestions in order to solve this mystery. My Caravan is running fine without any major repair for the last 10 years. The van is not overheating at all but... It spitts the coolant once in a while. I need to refill it once a week and it is usually a half a gallon. The radiator is not leaking anywhere else but after driving lets say 20 miles I can open the cap with no problem. This thing is not even hot!!! Not to mention that there is no pressure. I have opened it once when the car was running and yes there is a flow so it looks like the water pump is OK. As I said the dashboard temp gauge works OK. So the question is - is something clogged? I plan to flush the system on a weekend and maybe replace the thermostat but I'm not sure if that is it.
Any idea?
Thank You!

 

add a new rad cap when you do the stat
most importanly does the van make good heat?

 

Yes. No issue with that. I get the heat inside the van. How important is the radiator cap? What impact does it have?

 

When you say "spitts collant" do you mean that you see it coming from the cap? If so, then yes, replace the cap. If not, it very well could be the water pump. Water pumps have a weep hole that starts to leak coolant when they are failing.

 

No, the coolant spitts through the recovery container. It appears that the container is getting full and the "overflow" is removed via a rubber hose down at the radiator.

 

if the spring in the cap is weak it will not hold the pressure required to stop the coolant from boiling over. (needs to be under pressure to increase boiling point) Think of moms old pressure cooker

Worst case scenario you could also be getting cylinderpressure into the coolant (bad head gasket) this can push coolant and bubbles into recovery tank as well. I hope this isnt the case though that wont be as c heap as a Tstat and cap
(u can have some coolant tested to confirm this)

 

It appears that I may have an early stage of head gasket issue. The van has 204k on it and never had any major repairs. The thing that makes me wonder is the coolant and radiator temperature. Just a few hours ago when the engine was cool I poured extra coolant and started the ending with the rad cap off. I waited until the engine got hot with the heater on full and the coolant was still cool. The engine does not overheat. Defective water pump? It is not leaking and what are the chances of it getting bad? The fans turn on and I can see small bubbles once a while. The plan is this weekend to flush the whole system, replace the thermostat and read cap. Has anybody have any experience with permanent head gasket sealers? There are about half a dozen different brands in Autozone. I wondered how effective they are and if its worth a game. Any idea about the cooling system and its temperature?
Thanks