My vans themostat shows it is overheating in very hot weather, >95 degrees going up a grade or > than 100 degrees. If I turn off the air the thermostat returns to normal. I have had this checked out at two different repair shops and they find nothing wrong. The heater and air condition works but is slow to cool or warm and the blower is not very effective. Ideas, solutions? Thank you.

What is the weight of the oil? Heavier oil will cause a sluggish start/spin in cold weather. 15W40 is heavy. This can kill a battery in no time. Other problems are related to hot/overheated problems.

natural for engine temp to rise in Traffic - Until Themostat opens ) cooling fan sensor kicks on fan . But Antifreeze is not just a Cold weather item . Coolant is Absolutely Necessary for Hot Days . You must be full to recovery bottle setting of cold when checked prior to start up . Coolant for your make / model is Reddish - Pink colour and should have a reading of -25 thats negative 25 degrees the Lower the Better even - 50 .. Why ?? - 50 is 50 %% antifreeze / Coolant Concentrate MIX Gives Hot weather cooling Ability or very cold weather starting / winter HEAT .

There are many different temperature ranges of thermostats. The old one may have been a 165 degree thermostat. The new one may be a 195 degree one. You will then notice that the gauge will run higher than it used to.

Maybe needs a new radiator, thermostat, how is the water pump?I had this engine for 400.000km.

Motor oil thickens when cold- on very cold days, some grades of motor oil can be nearly the consistency of honey. It takes time for the oil to make its way from the oil pan to the top of your engine.

The ticking you hear is usually caused by the valve lifters running nearly "dry" - meaning that they are getting very little oil. As your Cruiser warms up, the oil thins and makes it "up top" much easier, so the noise decreases.

Make sure that you are following your manufacturers recommendation for the grade and viscosity of oil (example: SG SAE 10W30) for the temperatures you are operating your car in. In extreme cold weather environments, such as Chicago or Milwaukee, you may want to use an even "lighter" oil (example: 10W20 instead of 10W30) - you just have to be certain that when spring arrives, you go with the higher viscosity oil- your manufacturer normally covers this info. The grade (example: SG) is very important because it refers to the detergent content of your oil.

No vehicle manufacturer that I am aware of recommends a "straight grade" viscosity oil (example: SAE 30) in cold weather. Multi-grades, which act "lighter" in cold weather are called for.

The "W" in the oil viscosity designation means "winter" - it is the viscosity of that particular oil at 0 degrees F..... For example, "10W30" oil is as thick as an oil with a viscosity of 10 at 0 degrees F, and is as thick as an oil with a viscosity of 30 at 70 degrees F.

Pretty Cool, Huh?

It is not a good idea to use any oil thickening additive (STP, motor honey, etc...) in cold weather because they tend to add even more viscosity.

"The Court is out" regarding teflon additives such as "Slick 50" to your oil- the principle sounds good to me, and I have used them myself. Personally, a similar product has seemed to help tone down the "startup ticking" I myself have experienced.

No problem,just do not go to a 10w series oil weight

Change the mass air flow sensor (maf) . Summer months tend o be humid, this could cuz the sensor to react strangly and alter the Stoch/richness or the air-fuel mixture....Check it out tell if it its helpsful, if not There are acouple others we can look at..

100 degrees f? That is way too cold Either you have the wrong thermostat or it is wide open. 180 degrees is nominal and give you the best performance.. With AC on, expect 190 to 200 degrees. We are talking farhrnheit and not ccelsius, correct?

For a 95 Chevy Silverado....I replaced the Blend Door Actuator on the passenger side. Just behind the slide out cup holder. Yo ucan acces easily by removing the ash tray piece and the glove box....Or just the glove box and work like hell to get a socket in a tight place.

There are 2 actuators....one controlling the (Mode and Temp 89018681) and the other the (Air Inlet 89018367). I called the dealer and the parts were 85-125. I got it From TBA Auto (local store) for 39.00. A 20 min job at most.

check your coolant leval. and have the thermostat replace if the collant is ok in the radiator and holding tank