Challange for you techys

Based on your post here are a couple things to try. 1) you suspect waterpump. So take one hose off and turn the pump either by had or blip the key /starter but do not start he car. If the wp works it will puke some coolant. Big deal it is only coolant you can wash it off. 2) You have funny sensor symptoms with cold spots. Well from what I know of headers there should be water in there. Loosen the sensor on the header tank. Start the car and get it warm. Back out the sensor before you have boiling coolant on you and some coolant should leak out increasingly more as you back out the sensor. If you got juice you have flow here and it should make it to temperature. 3) you can boil some water and dump the sensor in while the car is started and before the coolant puke all over the place and gets hot. The cooling fans should come right on with start-up id the sensor circuit is working. 4) the sender circuit is a on/off deall just making a complete circuit so if you just unplug the sensor and short the wires the sender circuit should turn on the fans.

 

I'll take a stab at this one.
A. Have you checked the coolant level? I don't want to insult your intellegence, but it's the first thing to check.
B. If the coolant level is OK i.e. about two inches down from the filler neck in the expansion tank, have you burped the system? An extreme case of air being trapped in the system could cause circulation to cease. The procedure for this is pretty straight forward. Jack the rear of the car so that the coolant expansion tank is the highest point of the cooling system. In other words jack the left rear of the car up. Remove the filler cap and bleed the system. If a 328 is the same as a 308, there should be 2 bleeders. One on top of the thermostat housing the other on the top right of the radiator. Top off the coolant level and crack the bleeder on top of the t-stat housing using a 13mm wrench. If air is in the system it will bubble as it escapes through the bleeder. Bleed until you get a steady trickle of anti freeze. Then you can move on to the radiator itself. The bleeder is located on the right rear right on top. It's a knurled thumb screw (usually brass) that you shouldn't even need a wrench to open unless someone cranked it on too tight or it's corroded. Lefty loosey on that bad boy and bleed the rest of the system. Finger tighten firmly when finished, start the car and look for signs of circulation in the expansion tank. If all looks well top off collant level and replace the cap to the tank. Whalla! Bled system.
If that doesn't help the cause. You need to remove the right rear tire and inner fender well. This will have the water pump and belt starring you in the face. If your alternator light is NOT on and you don't hear any squealing from the belt when you rev the car, it's probably not the belt. Again, this is based on a 308 QV which has the same belt driving the H2O pump and the alt. If the belt is slipping or broken all together it should/will trigger the charge warning light on the dash. If you should happen to need a water pump, they are pretty straight forward to replace for someone with average mechanical skills.
If none of the above has any effect, I have one last suggestion. Make sure the coolant to water mixture is 50/50 or less. A mixture stongly biased to the anti freeze/coolant side can, in extreme cases, cause the coolant to foam effectively cavitating the pump and preventing it from working properly.
Anybody that has been in sea foam or a strong boat wake on a jet ski can tell you that excess air renders a fluid pump useless.

Good luck. I hope you solve the problem. Nothing is worse than having a car as special as a 328 and not being able to drive it on a sunny afternoon.

One last free word of advise: Don't drive it in this condition. Fixing a cooling problem will seem like a walk in the park compared to throwing head gaskets at it if you cook it. Ten miles is way to far to drive in it's current condition.

Again good luck,
John

 

Could it be a partially blocked radiator?

 

1. Check all coolant levels.
2. If possible run the car without the rad cap on, look for water movement, no water movement, either water pump or blocked rad as you have replaced thermostat. Did you bleed the system after replacing the thermostat?
3. DO NOT DRIVE THE CAR. These temperatures are head gasket killer temps.

 

Hi............

If you can reach it, run your hand over the surface of the radiator. If there are any cold or cool spots, the tubes are obstructed by rust or particle clots and the radiator should be flushed out or the core should be replaced with a new factory version or an aftermarket one.

Simple test for uniform flow through the radiator.

Or you could use one of the "new fangled" infrared temperature gauges from a distance.

Good luck !!!!!

Frank........23005
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