van overheats when driving on the highway. headgaskets, water pump and thermo has been changed over the last few months. any advice?
Assuming coolant level is up and thermostat has been tested and working, check for exhaust restriction and lastly have the gauge checked to see if it is functioning properly.
Also, consider a plugged up radiator. If the radiator has cold spots across it, some of the tubes can be blocked up and restricting flow through it.
thank’s guys I will be checking
yes it will lose coolant
Is the lower air dam (or deflector) still in place? These often get knocked off by curbs, rough roads, or animal strikes on the highway, etc.
If the deflector is missing an engine can overheat at highway speeds. A missing deflector will have little or no effect during in-town driving and no effect at all during idle.
air dam is still there
Cooling fan cycling on as it should both as to engine temperatue and when the A/C compressor is engaged?
If the fans are working then the possibility of a clogged radiator mentioned by BustedKnuckles would be the prime suspect.
That 3.8L engine had a bad reputation for blowing head gaskets and cracking heads. Your situation is indicative of a head sealing problem.
When the heads were off were they checked for cracks and warpage?
Might be worth it to try a new radiator cap. If the pressure doesn’t hold, the cooling capacity diminishes. May not work, but radiator caps are not very expensive.
Is this a shop replacing these parts, or is this something you’re doing yourself? If it’s a shop, try another shop.
There are a number of tests that can be used to diagnose overheating problems on a system that’s not suffering from leaks, including but not limited to
a pressure leakdown test on the cylinders to check for headgasket failure
thermally “mapping” (scanning) the radiator for temperature anomalies suggesting clogged tubes
flow testing for water pump function
flow testing of the radiator
testing of both/either the radiator cap and the T-stat
And if you have a radiator that is used to cool both the coolant and the tranny fluid (automatic trannys only), you want to check the condition of the fluid incase you have mixing going on in the radiator.
Others here can probably add to the list.
I think you’ll find the root cause of the problem far more successfully with diagnosis than with parts swapping. Normally, if there’s evidence to support it, I’d just recommend changing the T-stat or radiator cap, but at this point I think it’s important to find out of you have a head gasket breech and if not what the actual problem is. Continued overheating will damage the engine, and it’s important to get to the root of the problem without further ado.
Post back with the results. We do care.
You could try another radiator especially if you can get one with an extra row of cores,all these Ford minivans that set around in the backyards around here had basically the same problem,people loved them(Shame on you Ford for not making it right)-Kevin
parts changed by a shop
Pressure test in order I think.