Demetris said:Verify the overheating with an independed thermometer (infrared or else).
Demetris said:Lean mixtures and retarded ignition promote overheat, so check that they are correct for your engine. Free flow exhausts and / or air filters cause the mixture to lean out. Standard needles are not good any more.
Demetris said:If i remember correctly you removed the engine driven fan and installed twin electric ones or something like that. Perhaps your installation is blocking airflow from the radiator where it is needed most. Motorway speeds. If you can make a try run without the electric fans fitted you will be able to verify this. When i fitted the A/C to my P6, the airflow loss from the installation of the condenser and the small electric fan in front of the radiator, made the car run hotter at motorway speeds, even with the A/C off. To compensate, i relocated the front number plate to help the airflow through the lower valance.
Demetris said:If everything turns out to be OK with the above and you still have the problem, i would suspect that something must be wrong with your new water pump. Unfortunately, sometimes even new parts, fail to perform according to the required specifications.
1396midget said:I've got KO needles in mine - a bit richer than standard to take care of the free flow filters and loss of one silencer. Simon BBC electronic dizzy that's been OK so far. Will give timing and mixture a go again (keeps me off the streets)
1396midget said:Cheers, I'll give that a go. The problem started before I changed the fan mounts. Possibly turning them on at high speed might help? Can't remember if I built the fans so they could come off without taking the rad out...
Demetris said:1396midget said:I've got KO needles in mine - a bit richer than standard to take care of the free flow filters and loss of one silencer. Simon BBC electronic dizzy that's been OK so far. Will give timing and mixture a go again (keeps me off the streets)
It is actually the exhaust changes that you have introduced that might cause a problem at mid to high engine speeds. Unfortunately only on a rolling road you can find out what really happens. There is no point spending too much time adjusting the mixture strength at idle. Another way around this is to fit a wideband lamda sensor and go for a drive. I think that one or more of the forum members (Quattro?) has one fitted in his P6B.
1396midget said:Cheers, I'll give that a go. The problem started before I changed the fan mounts. Possibly turning them on at high speed might help? Can't remember if I built the fans so they could come off without taking the rad out...
The problem is that the fan motors and brackets represent blanked out areas on the radiator core. Turning the fans on when travelling above say 60 mph will have no effect on these blanks, while the airflow speed is already naturally high. Modern cars that were fitted from the factory with electric fans, probably have already taken into account these blanks due to the fan itself and have a larger radiator area to compensate. As you understand this is not the case with our cars.
symes said:Dont mean to sound stupid--bit is it possible there's blocked waterways in engine block by any chance---
ghce said:I remember another thread from last year that noted differences in current available water pumps and original pumps and overheating problems associated with the new less effective ones.
colnerov said:Hi, I always put a smear of Hylomar around the waterways on the pressed tin valley gaskets.
Because I'm not a very trusting soul. :roll:
harveyp6 said:colnerov said:Hi, I always put a smear of Hylomar around the waterways on the pressed tin valley gaskets.
Because I'm not a very trusting soul. :roll:
+1 for that.
Presumably composite valley gasket won't go with non-composite head gasket? Is it another tin one I'll need or is there enough tolerance in the arrangement to fit the fatter comp one?