98 TDI , no oil pressure

T

thysmar

Member
Joined
Jun 10, 2008
Location
Milford, Nova Scotia
TDI
98 Jetta TDI
low oil pressure light came on when first started, checked with mechanical gauge: no pressure. Gear that drives vacuum pump turns when cranking, oil pump drive shaft where it meshes with vaccuum pump appears OK. over 300K on this car, could the pump be too weak to pick up the oil in cold weather ?
This happened once before at startup and a shot of the throttle made the ligth go out.
What is involved with access and removal of oil pump?
Any help appreciated
 
G60ING

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
The oil pump is accessible after the oil pan is off. 2 bolts hold it on after the pan is off.



 
G60ING

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
I will say that I find it VERY rare for these oil pumps to fail. I wonder if the oil pick up is clogged or if there is wear elsewhere causing low oil pressure.
 
G60ING

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
I didn't say they don't fail I just suggested that its uncommon.

Do you have any pics of the gears? I think the pressure relief valve failing is the most likely failure point.
 
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rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Take a look a the timing belt. Oil on the belt can cause funny stuff to happen as well. However, with the mileage you have, it's worth taking off the oil pan and looking. Have fun with that "hidden" screw by the trannie. Stripped mine because I couldn't get it to go in straight.
 
T

thysmar

Member
Joined
Jun 10, 2008
Location
Milford, Nova Scotia
TDI
98 Jetta TDI
Thanks for all your pointers, I'll pull the pan this week and remove the pump. Does not sound too difficult.
My gut feeling is that the screen may be clogged or there is enough wear on the pump to prevent oil pickup when temperatures are cold ( below 0 F).
 
T

thysmar

Member
Joined
Jun 10, 2008
Location
Milford, Nova Scotia
TDI
98 Jetta TDI
Hi Guys, I pulled the pan and oil pump this evening and even though there is significant wear on the pump gears, shaft and housing I did not feel this was the root cause. After very close examination I found the relief valve plunger stuck open leaving a 3mm opening between suction and pressure. A little pry popped it back in place. I have not decided to replace the pump at this point. If I can remove the relief valve and polish the plunger so it moves freely I may consider this, if not it will happen again.
Looking back we had a cold snap some time ago and I suspect the pressure got so high when the engine was cold it forced the valve open and it stuck in this position.
The intake screen was very nice and clean, the oil was in good condition as well.
I will price a pump and decide from there.
Thanks for your help.
 
paramedick

paramedick

TDIClub Enthusiast, Vendor
Joined
Jul 29, 2001
Location
Versailles, Kentucky
TDI
2015 Audi Q5 TDI
thysmar said:
Hi Guys, I pulled the pan and oil pump this evening and even though there is significant wear on the pump gears, shaft and housing I did not feel this was the root cause. After very close examination I found the relief valve plunger stuck open leaving a 3mm opening between suction and pressure. A little pry popped it back in place. I have not decided to replace the pump at this point. If I can remove the relief valve and polish the plunger so it moves freely I may consider this, if not it will happen again.
Looking back we had a cold snap some time ago and I suspect the pressure got so high when the engine was cold it forced the valve open and it stuck in this position.
The intake screen was very nice and clean, the oil was in good condition as well.
I will price a pump and decide from there.
Thanks for your help.
Click to expand...
$100. What's your engine worth?
 
G60ING

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
If you like cornering hard get the windage tray oil pan gasket and the baffle too.
 
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