Low Oil Pressure on Hot Idle

bvlmv · **Joined:** Fri Jan 18, 2013 8:57 am **Posts:** 49

Hello to all.

I've been getting a low oil pressure alarm on my dash after the engine is hot and idle (0- 10 PSI). So far I've changed the sendor, switch, oil grade (20w50) and finally the dash so I'm thinking it's something internal. When the alarm goes off the engine feels fine and doesn't hesitate at all. The oil pressure returns to normal (40-60 PSI) when I start moving again.

Anybody experience this on their VP engine?

BTW I have a 99 Horizon 220 with a 5.0Gi PWTR

Thanks in advance!

joet · **Posted:** Wed Apr 16, 2014 2:41 pm

Put a mechanical oil pressure gauge on it and see what it shows. I had the same problem and it ended up being the notorius VDO dash, mine would also peg the temp gauge if I had the pump to blow up my tube plugged in while the engine was running.

ric · **Posted:** Wed Apr 16, 2014 3:02 pm

Faulty oil pump, a bad cam/main bearing, etc.

Or just a bad gauge. Verify with a mechanical gauge.

bvlmv · **Joined:** Fri Jan 18, 2013 8:57 am **Posts:** 49

I'll try that next time I head out.
Let's say the gauge also shows low oil pressure when hot idle. Is it possible to single out exactly what the issue is (oil pump or bad cam/main bearing, etc.) without taking out the engine? Any additional test? I'm already preparing for the worse case scenario and just want to be ready to talk the talk with the mechanic.

NiagaraChillin · **Posted:** Wed Apr 16, 2014 6:05 pm

I know this is a dumb question, and I'm not trying to insult your intelligence. But, did ya check the oil level? Low oil will cause this type of thing. Also, you said you replaced the dash? VDO, or a new cluster? Like joet said, VDO's are notorious for faulty readings.

If it is the pump, the engine has to come out. Mechanical gauge will tell you, hopefully its just a bad dash gauge.

bvlmv · **Joined:** Fri Jan 18, 2013 8:57 am **Posts:** 49

Yep, that was pretty much the first thing I checked. This was happening with the VP recommended grade so I switched to 20w50 but no luck.

Do you or anybody know where I can find a T type of connecter so I can have the sender and mechanical gauge connected at the same time?

pickledboater · **Posted:** Thu Apr 17, 2014 7:00 pm

One other thing to try before you go to major repair mode. I started using a k&n oil filter and the idle pressure on my 4.3 made a dramatic improvement. I'm told that the check valve in the k&N is superior to other filters, can't say that is a fact, but the pressure is better. Might be worth twelve bucks to find out.
ps. I run straight 30w Valvoline.

NiagaraChillin · **Posted:** Thu Apr 17, 2014 7:06 pm

bvlmv wrote:

after the engine is hot and idle (0- 10 PSI).

What is the engine temp reading when this happens? If it is idling hot, it could be thinning the oil.

deafwish · **Posted:** Thu Apr 17, 2014 7:44 pm

NiagaraChillin wrote:

What is the engine temp reading when this happens? If it is idling hot, it could be thinning the oil.

Even a 20w50 at 140C will supply sufficient oil pressure at idle.
Are you certain it was a 20w50 from a reputable supplier?
p.s. A 20w50 is an equivalent viscosity to a mono 30, but obviously a multi-grade.

NiagaraChillin · **Posted:** Thu Apr 17, 2014 8:01 pm

deafwish wrote:

Even a 20w50 at 140C will supply sufficient oil pressure at idle.

When my raw water pump impeller went kablooie and my temp gauge pegged, my oil pressure dropped to 0-10. Same thing with a buddys Merc 4 cylinder, his overheated and oil pressure dropped. Just a thought from what I have seen happen.

deafwish · **Posted:** Fri Apr 18, 2014 1:11 am

NiagaraChillin wrote:

When my raw water pump impeller went kablooie and my temp gauge pegged, my oil pressure dropped to 0-10. Same thing with a buddys Merc 4 cylinder, his overheated and oil pressure dropped. Just a thought from what I have seen happen.

Depending on the viscosity of oil used, this is very plausible.
All oils (even olive oil!) thins out when heated, even multigrades.

ric · **Posted:** Fri Apr 18, 2014 8:08 am

I would pickup some 20w40 synthetic from West Marine and a Mobil 1 oil filter. Start there.

NiagaraChillin · **Posted:** Fri Apr 18, 2014 1:53 pm

deafwish wrote:

All oils (even olive oil!) thins out when heated

I thought they only used that in Italian boats? :lol:

deafwish · **Posted:** Fri Apr 18, 2014 7:18 pm

ric wrote:

I would pickup some 20w40 synthetic from West Marine and a Mobil 1 oil filter. Start there.

If he has an operating temperature oil pressure issue, why would you suggest he use a thinner oil?!
Mobil don't make filters. Any OEM standards filter should be fine.

bvlmv · **Joined:** Fri Jan 18, 2013 8:57 am **Posts:** 49

pickledboater wrote:

One other thing to try before you go to major repair mode. I started using a k&n oil filter and the idle pressure on my 4.3 made a dramatic improvement. I'm told that the check valve in the k&N is superior to other filters, can't say that is a fact, but the pressure is better. Might be worth twelve bucks to find out.
ps. I run straight 30w Valvoline.

I'll try that. Thanks!

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Low Oil Pressure on Hot Idle

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