Overheating. trying to decide whether or not to pull the heads off my 3.8L caravan. promlem is that it over heats and is loosing antifreeze without leaking onto the ground while running. would like some other suggestions before replacing the head gaskets.

 

wondering what kind of tests i could run to see where all the antifreeze is going in my 3.8L caravan. thinking that its the head gasket but would liek to know other options before tearing the top end apart

 

If your sure its not leaking externally, then the First thing i would do is pull plugs out one at a time and put air into cylinder with radiator cap off, IF coolant bubbles up at radiator, that a good sign of head gasket, or cracked head. You could do it backwards, pressurize radiator and pull plugs, but it might not have enough pressue to show it that way, because your only going to get about 15-18 pounds pressure on radiator without hurting it. air in cylinder is a lot more so it should push it up thru radiator fill neck it its got a problem, How much coolant are you loosing?

 

Quite a bit I will fill it up and it will be overheating after about 1 mile of driving. Not sure how much is lost though just got the vehicle

 

They make a head gasket detector kit.Its a tube with a purple liquid .You open the radiator and stick the tube and it pulls air into the liquid and if it turns green you have a head gasket leak
http://www.amazon.com/Lisle-75500-Co.../dp/B0007ZDRUI

 

Yea, I have used them too. Sometimes they work good, Had an engine one time that was so small of a leak, it wouldn't work because the only time it was leaking was when it was hot out and running good and hot, the heat would finally open it up enough, I put air the the cylinders and it took a minute or so before it finally started pushing it out the radiator fiil neck, But they do work,

 

I have done compression tests and it's not the head gasket. Water pump was the problem I replaced it and the transmission cooling hose. I filled up the rad and woke up this morning to a puddle any ideas?

 

If it was not leaking externally before, the water pump can cause it to get hot, but it will not make it loose coolant so that you would have to add like you say you do. Also you say you replace the transmission cooler hose. That has nothing to do with coolant. What is the puddle, Coolant? Trans fluid? Also I was not talking about compression test. It's actually kinda backwards compression, Putting air in cylinder and pushing coolant out the radiator. You need to make sure you dont have coolant in you transmission, I have seen several radiators break and after you get a vehicle hot, then when you shut it off, as it cools down the pressure goes into the trans, Possibly what you might have since you have no external leaks but your loosing coolant, if not it about has to be a head gasket