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bw

Hi guys. Not been here for a while as have been busy recently.

Having a small problem with the '91 P4. It happens when it gets hot, like when you've slowed down for a few minutes in some traffic and temp gauge reaches 85 or 90 degrees. When I try to accelerate any more than very gently there is a sort of knocking/tappety noise and a distinct lack of power. The temp drops after a mile or two once you get going and it is then fine again with no odd noises.

Any ideas about what could cause a knocking noise under load when the engine is hot? Anyone had a similar noise? It's running on fully synth, so maybe the oil is not viscous enough at those temperatures and it's time to change to part-synth!!??

gritsop · Posted: Wed Nov 19, 2003 6:23 pm Post subject:

Hi,

Have you checked if the water pump is the source of sound? Most of the times the pump warns you with a kind of sound which is like a knocking one before actually going off.

Regards,
_________________
Thanassis Gritsopoulos
1991 Alfa 33 1.4 IE
2001 Alfa 147 1.6 Distinctive

http://www.alfa-restoration.co.uk
Parts Shop: www.alfa-restoration.co.uk/shop

bw · Posted: Thu Nov 20, 2003 9:56 am Post subject:

Hi,

Thanks for the reply. Hopefully it's not the water pump as I had a new one fitted 3,000 miles ago when I had the timing belts changed. Is the water pump knocking associated with a hot engine then?

gritsop · Posted: Thu Nov 20, 2003 5:18 pm Post subject:

Hi,

Knocking water pump usually means that it is near to the end of its life.
Since it cannot circulate the water properly, the engine gets hotter more easily.
What about the cooling system ? has it been cleaned recently?

Regards,
_________________
Thanassis Gritsopoulos
1991 Alfa 33 1.4 IE
2001 Alfa 147 1.6 Distinctive

http://www.alfa-restoration.co.uk
Parts Shop: www.alfa-restoration.co.uk/shop

bw · Posted: Fri Nov 21, 2003 11:28 am Post subject:

Unlikely to be the water pump then as it is only a few weeks old. Engine is not overheating, just getting up to 80 or 90 in traffic and then I get the knocking. Wouldn't the water pump knock all the time if it was faulty?

gritsop · Posted: Fri Nov 21, 2003 5:52 pm Post subject:

Hi,

Yes if the pump was faulty it would knock all the time.
Sorry I didnt undestand your writing when you stated the problem.
Now, I think something mechanical, inside the engine happens ; maybe camshafts or tappets not having enough oil but I cannot guess... sorry.

Regards,
_________________
Thanassis Gritsopoulos
1991 Alfa 33 1.4 IE
2001 Alfa 147 1.6 Distinctive

http://www.alfa-restoration.co.uk
Parts Shop: www.alfa-restoration.co.uk/shop

bw · Posted: Fri Nov 21, 2003 6:43 pm Post subject:

yes, I think maybe tappets. I'll try some thicker oil and see if the problem goes away Cool