QuestionIt's a 90'Caravan 2.5L with Turbo which has a fan for the A/C and a fan for the radiator.It did overflow the the overflow bottle.
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Followup To
Question -
Mr. Finston;
We just changed the freon from R12 to R134. We also replaced the cylinder head. The engine runs around 190 without the A/C,but runs hotter 200 -220 when we use the A/C.Could the A/c be the cause of our problem? What can we do to fix this?
Answer -
Hi Vic,
O.K. it's a 2.5L 4 cyl engine. Those can trap air in the thermostat housing if not filled properly which results in a false high temp opening for the thermostat. You need to drain off a couple of quarts of coolant (catch and reuse). Here is what to do. Start the engine and turn on the heater and set the temp to hot so as to open the heater core flow circuit. Let it idle until you feel hot air from the heater vents with the blower running. Then turn off the engine. Then open the drain on the radiator (but DO NOT remove the radiator cap) and collect a couple of quarts of coolant. Watch to be sure that the coolant empties from the overflow bottle first which tests the airtightness of the system. After you get coolant collected, close the drain. Then remove the plug from the top of the thermostat housing (located between the 3 and 4 spark plugs, using a allen wrench, 6 or 8 mm, I can't recall which). Then open the radiator filler cap and add coolant until you notice the level of coolant in the system rises into the thermostat housing and fills it to the top of the plug opening. Then put some anti-lock compound on the plug and put it back in its hole. Then continue filling until coolant level reaches neck of the filler. Then replace radiator cap. Then fill the overflow bottle to the indicated cold line.
That should clear out the air in the system, but watch the level of the coolant in the bottle for a few days because the level may drop as a little more air is bled from the system.
That should optimize the cooling system performance and may well result in a cooler running system even with the new type refrigerant in the AC system.
Roland
Hi Vic,
I would expect this sort of change because the thermal efficiency of R134 is lower than that of R12. A temp of 220 is not to be alarmed about. Although you didn't tell me the model and year the cars that have two fans don't bring into play the high speed fan until the temp reaches 230F. If you are running 50/50 coolant and not getting any boilover from the overflow bottle I would consider this acceptable. You might want to drain and refill the cooling system (collecting the fluid for reuse) in case there might be air trapped in it. Each model has its own peculiatities to minimize trapped air. Let me know the model and year and I can tell you about the proper procedure for your car. Because of often being "maxed out", use the "thank and rate" tab where there is a place to type in comments. I get an alert that you have responded.
Roland
AnswerHi Vick,
The fan(s) will always come on when you turn on the A/C even if the engine is cold. If you have 2 fans, one may be high speed, one may be low speed. And in the non-AC mode there is a different temperature setting, that is measured by the coolant temp sensor located on the side of the thermostat housing box, for activating each fan, typically. If you only had one fan it would be a 2 speed fan. I don't have the manual for a '90 van so I can't be certain how those temps are set, etc.
But in anycase, if the fans comes on (when you aren't using the A/C) and it (they) comes on more rapidly, or two fans instead of only one, as the temp gauge rises then that would suggest the fans and their control are fine. So I would first do the partial drain and refill as I described and see if that improves your situation. Also make sure that the top radiator hose gets hot which is proof of circulation thru the radiator.
Roland
