Castrol 5W50 low oil pressure!!

[kickster]

I have been running AMSOIL 5W40 or 10W40 in my VW jetta 2.0 for past couple of years. I never had any issues. 2 weeks ago I switched to Castrol 5W50. Ever since my valve noise has gone up and my oil pressure at idle drops to 9 psi (oil light comes on)
older VW engines love thick oil so I assumed with castrol 5W50 would be a better choice!
My idle oil pressure was around 15 PSI using AMSOIL 5W40 during Hot july days.

In the morning right after start up my oil pressure goes to 50 PSI with AMSOIL the needle would go all the way to the max (Over 80 PSI)

Why is Castrol 5W50 such a wimpy oil? I am thinking of dumping it and replacing it with good old AMSOIL

 

[moribundman]

I can't believe the 5W-50 is the problem. I used that for about 100k miles in my 2.8 Audi V6 engine with very good results. Maybe the oil pressure switch went coincidentally on the fritz when you changed the oil?

 

[kickster]

I doubt it. I have a factory oil pressure sensor plus a VDO sender that is connected to a VDO oil pressure gauge. oil light comes on when the gauge shows less than 10 psi pressure.

 

[unDummy]

I don't believe it either. And, I'm no Castrol fan.

To prove the oil bad, UOA it along with your Amsoil for comparison.

Too many variables affect oil PSI besides bottle label weight.

 

[oilyriser]

plugged oil pickup screen?

 

[kickster]

Why should I do an UOA on a oil with less than 1000KM on it? My oil pressure is low. I am not going to give this oil a chance to damage my engine. I will be taking it to track on saturday. I cant take any chances. Tomorrow it will be dumped.

 

[Gary Allan]

It's dyslexia ..you picked up Castrol 5w30 by mistake.

 

[kickster]

This is a new engine with less than 20,000 KM on it. AMSOIL was used in it since the day it was rebuilt. I dont think the oil pump is plugged

 

[Alan]

I used this on my prior VW GTI VR6 and experienced no problems.

Maybe a bad sensor or oil pump?

 

[kickster]

you mean bad SENSORS. I already said that I have 2 sensors and both reporting the same info. Oil pump will not go bad in 2 hours. This is a new pump.

 

[Ray H]

Pump lost its prime?

 

[Ramblin Fever]

From what I've learned with different viscosities, is that it could be any number of things, not just the oil.

Are you using a different filter then before?

Perhaps the Castrol is mixing with the slight remaining amount of Amsoil, giving you a not-so-good mix?? - as an engine will never totally drain ALL of the previous oil.

 

[kickster]

I will drain and refill with AMSOIL 10W40 this weekend. If the pressure goes back up then we all know what is causing the problem

 

[moribundman]

"we"?

 

[JohnnyLock]

I run 5W30 Castrol Syntec Blend(bring it on Castrol haters!)all the time in my 2.slow -- It hasn't mattered if I run 5w30, 5w40, 10w40, or 15W40, I always get valvetrain noise(hardly audible clicking) shortly after startup. My wife goes nuts when I am sitting at a stoplight and I turn the radio off to listen to the engine so I just quit worrying about it. I do not understand the physics of oil pressure too well and how a higher weight oil affects it but I do not believe it is because the Castrol is wimpy. I would go back to your old brand -- heck if it's 2004 or later you could even throw in some 5W30 of the brand of your choice and do not worry about the VW rating(if you're still under warranty). Next change I am going to try 10W30 but I do not expect to hear anything different. And as far as your new pump not going bad in two hours, yes it's is unlikely, but with VW quality on the Jettas it is not out of the realm of possibility. I've had the IV 99.5 model Jetta with the 2.0 and the 2004 2.0 and have had a myriad of problems with the 99.5.

 

[Audi Junkie]

As many here have heard, my BOSCH mechanic uses Syntec 5w-50 by the drum. He holds a full competition race licence and claims no oil holds pressure better at the startup line, after a warm-up lap, than 5w-50 Syntec. Draw your own conclusions.
My cousin's VW has an OP problem that only 20w-50 cures so far. For winter, guess which oil I am planning on using?

What your issue may be is a filter problem.

 

[vizvo]

quote:

---

Originally posted by kickster:
I doubt it. I have a factory oil pressure sensor plus a VDO sender that is connected to a VDO oil pressure gauge. oil light comes on when the gauge shows less than 10 psi pressure.

---

VDO sending units are not perfect. I'm very familiar with the combined VDO transducer/alarm switch. They can age and drift. When diagnosing oil pressure
problems, it is preferable to use a quality mechanical oil pressure gauge. You can hook up the mechanical gauge with a "tee" fitting to compare the VDO readout with the mechanical readout.

I'm not saying that you are wrong, but don't blindly trust VDO electrical oil pressure gauges.

I need to replace mine. Mine currently reads 20 psi when the pressure is actually 10 psi. It reads 25 psi when the pressure is actually 20 psi. It is accurate at 30 psi. It reads 35 psi when the actual oil pressure is 40 psi.

 

[slickfisher]

When you said rebuild engine, I lost my concentration. That is as likely the issue as anything. One thing to remember is that one is starting with a 5wt base oil that has additives to make it behave as a 50 wt oil when hot. I was right in the middle of the VW dynamic oil pressure warning system as a tech. 9 times out of ten it was puked out bearings from poor lubrication maintenance. The spec for the older VW inline fours was not less than 29 psi at 2000 rpm with engine hot (rad fan cycled twice). You live in a cold climate so you need a thin oil for start up. Sounds like just the thing for good old GC. I would try an oil with closer weights. Like a 10wX or even a 15wX. Yes you loose start up protection. Then I would do a mechanical gauge test to see if you in spec. My guess is you have excessive clearance somewhere in your engine.

 

[oilyriser]

If the 10w40 cures the problem, and there really was something wrong with that Syntec, Castrol would probably want to know about it. Maybe they'll give you a free case.

.

 

[mdocod]

reminds me of the time I tried Quaker State 5w50 synthetic... The same thing happened in my engine. I noticed significantly lower idle oil pressure than with other oils... even GC made more pressure at idle than the Quaker State 5w50. I remember.. vividly.. when pooring the QS... it almost seemed to poor and drip from the bottle more like water than oil... it's didn't form the usual "string" of oil when pooring the last few drops from the bottle, but rather, it dripped, like water draining off the walls of the bottle. It ran fairly well on that oil, but the low pressure scared me. My feeling is that, 5w50 oils that are formulated from hydrocracked dino (group 3) (like syntec and QS) are just not working as intended.

I wonder if these oils are partially spinning in the pump rather than getting pumped at idle. just a thought. i don't see why it would happen, but it's the only thing i can come up with.