Oil pressure and vacuum problem sometimes

33B

Member
Joined
Jun 15, 2021
Location
Bosnia and Herzegovina
TDI
1.6TD 51kw Passat b2 '87; Touran 2.0 TDI PD 125kw '07
So I have a '87 Passat with 1.6 td. Sometimes when I start the engine the oil pressure light comes on and also no vacuum(stiff brake pedal). As soon as I rev it oil light goes away and I get vacuum (soft pedal) and no problems after that. Doesn't matter if engine is cold or hot.
Does vacuum pump need oil pressure to function correctly, if not is the intermediate shaft not spinning or getting stuck?
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2005 BEW Wagon
The intermediate shaft drives the the vacuum pump shaft which drives the oil pump, so that's why your symptoms are related.

As to why this is happening... the most common cause is the tang on the bottom of the vacuum pump shaft OR the slot in the oil pump driven by the tang (or both) wear out. One bolt to pull the vacuum pump out and you can have a look at both parts.
 

33B

Member
Joined
Jun 15, 2021
Location
Bosnia and Herzegovina
TDI
1.6TD 51kw Passat b2 '87; Touran 2.0 TDI PD 125kw '07
The intermediate shaft drives the the vacuum pump shaft which drives the oil pump, so that's why your symptoms are related.

As to why this is happening... the most common cause is the tang on the bottom of the vacuum pump shaft OR the slot in the oil pump driven by the tang (or both) wear out. One bolt to pull the vacuum pump out and you can have a look at both parts.
I just installed a brand new vacuum pump, because on the old one the white part with one way valve broke. Symptoms didn't change regarding to oil pressure light. What to look for when looking at the oil pump shaft? Havent seen anything alarming.
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2005 BEW Wagon
The oil pump drive has a slot that the tang on bottom of the vacuum pump slides into.

The slot can wear and cause the oil pump to skip.
 
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