Heat into the cabin. Summer time ia a problem for my car. When I drive on the highway and the engine really works - often when the overdrive hits in - I get a lot of really hot air into the cabin. I have tried to lock the vacuum valve to prevent hot liquid into the heater panel. Valve is closed - put same heat. I also have problem with regulating heat into the coupe. Either cold (all the way down) or hot adjusting just a few mm upwards. 4,3 litre engine

Hi Fred.

I'm not totally sure I understand your question, but I'll take a shot. Are you saying that the engine fan stays on all the time for your car, keeping the radiator cool, and so you're not able to get any heat in the cabin air? Or possibly that the cabin fan is on all the time and you can't get any heat because it's keeping the radiator cool.

unless there is something very odd about your car (or you're living at the south pole), your engine coolant will be plenty warm within a few minutes of starting. If you are doubtful, drive the car for 5 to 10 minutes, stop, turn off the motor, pop the hood, and carefully move your hand close to the radiator. The blower fan helps transfer heat, but that's to move the coolant temp down probably into the 150-200F range.

if you're not getting any cabin heat, I'd have stronger suspicion about the heater core for your air system. In the majority of vehicles, there is a loop of coolant that comes off the back of the engine block, through the fire wall, and up to a U-Bend of pipe. When the heater is off, the coolant is just re-directed back to the engine. As you turn the knob or lever for cabin heat, it'll turn a switching valve to shunt the hot coolant into a heat exchanger/mini-radiator that the cabin air blows past. This system being a mini-radiator is why highways with long uphill grades will advise motorists to turn on their heater full heat, highest fan, when climbing in the summer. it's an additional way to keep the engine from overheating, even if it sucks for people in the vehicle.

Depending on the car, it can be either easy or really involved diagnosing or repairing the heat exchanger. if you go this route, you'll want to make sure that the coolant is circulated through the core thoroughly and that the coolant-system is de-bubbled.

Good Luck!
D

Try hitting the blower motor with a hammer handle and see if it starts, if it does replace it.

When in Overdrive the output shaft of the transmission will turn faster than the engine rpm. So overdrive is only useful when on the highway. This will conserve fuel. The option to turn overdrive off on the highway would be useful in mountain driving or pulling a trailer.

1-your thermostate is stuck open half way. thermostate is a simple device that made of enlarging metals when heat is applied. it suposed to be in close position to allow engine heat up, when specified temp reached it opens and let it flow and radiator tries to keep coolant cool.when it is broken it stucks or it acts slow or it wont acts at all. in your situation it is stuck open half way. it allows enough water to be heated but flow is limited to heat cabin heater.

2-if there are cabin heater selenoid/selenoids for two different temperature for cabin left and right, on some instance those selenoid valves to adjust cabin heater stuck open or closed like thermostate acts on first case. so heat is not enough to heat up cabin heater.

The OD is a extra gear do you need it not really you can drive 150 miles if anything its the switch button that went out

overdrive is for highway driving, lowers your engine rpm's and saves gas-allows the engine to not work as hard at higher speeds. Not desirable in around town traffic, and if you can lock it out if you do most driving under 45mph, a good idea so you don't 'lug' your engine.

this is really not a problem, overdrive will only be used if car speed is up to speed for it to engage and that is how its designed. If you pull a trailer or if you are in a hilly area and your car keeps shifting in and out of overdrive you should turn off untill more flater terrain, otherwise it doesn't hurt your vehicle.

Drive the vehicle in "D". The D selection is the overdrive. You can consider the overdrive as a fourth gear. The D3 is simply third gear, and if driven in D3, the transmission will never shift into overdrive when needed.

well overdrive is really where your suppose to have it when you hit the highway. Seem now the gears are slipping in (D) mode. if you want to save more time go to any major parts store and purchase TRANSX. pour it in and drive off.