High Pressure Then Wouldnt Restart

[TaffyTim 6]

My Mi doesnt seen to like sitting still or moving very slowly as its causing the oil pressure to drop really low. So much so that at idle the oil pressure warning light will come on and with that so will the stop light. When I apply a few revs the pressure picks up and the light goes out, but as soon as i come off the throttle the stop light will come back on.

 

It did this last week when i was moving slowly around my street trying to find a parking space after sitting in really heavy traffic (this is when a crown wheen bolt shot through my gearbox). It also happened last night. All seemed well until I sat still with the engine on for 5 mins. When i pulled off the oil pressure was doing the same as above. I drove for 5 mins trying to keep moving then pulled into a shop and stopped the engine. When I tried to start it up the starter motor was only turning very slowly and the car would not start up, I tried to bump it but had no joy from that either. I went back to the car 1 hour later when it had cooled down and it started straight up with the oil pressure sitting at the half way mark.

 

My oil temp gauge doesnt work so I cant see what that was doing but its got to be fair to say that the oil must have been hot. My water temp was high but not the highest it sat on the 2 bars from top and the warning light was not on.

 

Ive got an alloy sump which is supposed to provide enough coolingfor the Mi. I do get alot of mayo in the breather pipes and filling tower since the replacement of the head gasket could this have an affect on the oil temp?

 

Im not sure what oil pump is in there but the last owner provided a receipt for a group A spring.

 

All suggestions apreciated.

 

Tim

Edited February 18, 2007 by TaffyTim

[Alastairh 47]

Try a new pug oil pressure sensor before you go spending lots of money, as these can often give out miss readings.

 

I presumed you've checked your oil level etc?

 

What oil do you run in it?

 

Alastair

[sorr 0]

Try a new pug oil pressure sensor before you go spending lots of money, as these can often give out miss readings.

 

Alastair

 

If it shows low pressure on the gauge and low pressure/stop light is on then unlikely to ne the sensor as the two are independant. So most likely something else, in your case 2 something elses an oil pressure issue and 'hot' electrical problem.

 

But as Alastair says check what oil you have in it and start from there.

[TaffyTim 6]

The low pressure sensor is quite new as the old one failed a little while ago, but as sorr said the actual pressure sensor was showing a low reading which shows the pressure was low.

 

Im not sure what oil it was filled up with when i got the baffle put in, Miles filled it last, Can you remember Miles? (Im assuming you will read this).

 

On top of whatever Miles has put in I have put in a letre and a bit of Halfords 10w/40 enhanced mineral oil as the level had dropped down to the min mark, it now sits just below the max mark.

[TaffyTim 6]

Miles used the Semi Synth from GSF approved by VW/Pug oil and reminded me that i have an GTi6 oil pump and drive chain/wheel.

[TaffyTim 6]

Any more ideas would be apreciated.

 

From looking into this problem it seems that low pressure like this indicates worn big end bearings. After thinking about it, after i had the baffle put into the sump my cold start pressure used to be off the scale, but now it sits at about 3/4 of the scale, which is a decrease (to state the obvious).

 

If it is the big end gone what does it mean? Old posts mention alot about needing new bearings and a crank regrind. How costly is this?

 

Can someone tell me what it means by the big end going. How does it result in producing lower pressure and higher oil tem. When I was filtering through 18 pages of search criteria i didnt come across this explanation.

 

ta

Tim

[Hilgie 16 2 Cars]

If the crank is not damaged a regrind is not needed...just a whole lot of new bearings (I would replace both main, thrust and big-end bearings) and some new crankshaft seals. Replacing the main-bearings is an engine out job. Replacing just the bigend bearings is easier. Sump off, remove oilpump and start replacing.