Van overheating, ideas?

[AntrimMan]

Richard,
are you putting too much faith into the accuracy of the gauge? Any other gauges acting oddly? The heater only adds a small heat exchanger to the circuit and your QUICKLY statement makes me initially suspect the guage, as the heater motor will draw a fair bit of current.
Is the rad core blocked by dead bugs or leaves or something?
Is the overheating actually happening? If so, and the heater helps cool it down, it is likely a core blockage but try the easy things first. With the cap off and the engine cold and the heater off, there should be little visual flow in the rad. The flow should increase as the engine warms. Continually feel the rad hose carrying the hot coolant from the engine where it meets the rad, you will know when the thermostat opens 'cause it will get suddenly hot and the flow will increase dramatically. If the engine gets hot, you can rev it, you don't have to drive it, and the hose doesn't, bingo, guess whats bad. If the thermostat is replaced with a known good one and the problem persists you should have the rad flow tested. Most shops will not repair rads today, they will offer a new one instead. Boneyards are less expensive but you take your chances. A new rad is less expensive than a cooked engine on the side of the highway on a rainy night with no street lights around. Don't lend money to family, make it a gift instead, that way they won't beat you out of it and may return the favor someday.
Best of luck,
Martin

 

[LBrown59]

Is the fan running backwards?

 

[johnk]

Timing could be too far advanced.........

 

[Rch]

I had an '89 Lincoln that acted kind of like that. After changing the thermostat didn't help we discovered that a head gasket leaked in such a way that, during the compression stroke, the fuel/air mixture was pushed into the water jacket near where a heater hose connected and blocked the circulation to the heater. At higher RPM's ( 2500 or so) this "burp" would move on and the heater would work. If it sat at idle for 7-8 minutes it would have a volcanic eruption as the "burp" got big enough to "belch on through" to the radiator so to speak. With driving , the RPM's were enough to keeping the burp moving through the water jacket a little at a time. It did not have a detectable miss and didn't use coolant. Depending where the air/fuel leak was and realizing coolent was not leaking back into the cylinder this could explain what is going on. Running the heater may bleed off the "burp", allowing the water to recirculate - kind of like vapor lock. A compression check may help . The head gasket replacement was an $ 800 job, fortunately under warranty. /forums/images/graemlins/shocked.gif

 

[MikeFromVA]

Bought a 93 Honda Civic on eBay last month and it had similar symptoms - turned out to be a leaking head gasket. Hope that isn't the problem...

 

[GaryK]

You mentioned bubbles in the radiator, this is an indication of air in the system, either it needs to be bled(some vehicles need this if the fluid has been drained etc due to the configuration of the hoses and rad etc) or the engine has an internal air leak into the cooling system such as a head gasket etc. sometimes you can see some oil skim on the water as it flows by the cap. the roiling and heavy flow you see once and awhile is probably the thermostat opening and closing. You don't mention how many miles on this van, etc so the list of possible ailments is endless. Try a compression test, its usually easy but on a van?????. someone mentioned getting the rad cleaned......like another post, most rads today are throwaways with plastic tanks...

 

[Ozarker]

Had to replace two clutches.........replace water pump. The pump shaft has too much runout and is shaking the clutches to an early death.

 

[slowrev]

Update info: He put some kind of “coil cleaner” (for air conditioners??) in the radiator. Evidently it’s similar to “CLR” and is supposed to remove deposits. It foamed up like a volcano you might have made years ago (baking soda/vinegar). Some of the rods in the radiator seem to flow water & he thinks a couple others might be clogged.
//

My vote is mineral buildup in the radiator cooling tubes. Professionally clean or replace radiator.

Ben

 

[normde2001]

It would sure help to know what vintage, type, brand, model, etc., van we are talking about here. Overheating is very common and is normally cured by replacing, rad cap, then thermostat, (including flushing, changing coolant). If it's one with a "doghouse" in the driver's compartment, pull it out, or whatever is necessary to get to the thermostat.

 

[hudr]

Does the van have an automatic tranny? We had a '79 Pontiac that would overheat running down the road, but not at idle. We went so far as to install a 4 row radiator and it still overheated. Come to find out the torque converter in the tranny was pumping enough heat into the radiator (through the trans cooler built into the radiator) to overheat the motor. We pulled the tranny, swapped the toque conv. and the problem was solved.