high oil pressure?

[whatvan]

Recently, on a road trip from California to Vermont, I began experiencing higher than usual oil pressure.

I changed my oil before leaving Idaho for Cali. The van is an 89 4wd manual and has 161,000+mi. I was running 10W-40. Everything ran at optimal levels.

On the trip from Cali to Vermont, daytime temps were in the 90s and I was maintaining a speed of about 70mph (slower up big hills) at about 3000rpm. I drove a stretch of 1000 or so miles on the third day of the drive. I wasn't losing any more oil than normal, and I had run through some coolant. However, towards the end of this day I noticed the oil pressure had increased when the temps were up, but after sunset everything would run at acceptable levels.

Upon arrival in Vermont I changed the oil and filter. I opted for 10W-30 thinking that may be part of the issue. I drove about 50 miles after the oil change. The first 25 everything ran smoothly averaging about 40mph (50mph max speed) at 2500-3000rpm, but the second half of the drive the oil pressure increased.

My best guesses are possibly a faulty relief valve in the oil pump or a faulty head gasket (neither task I'm overly confident, or well prepared, to do myself).

Searching this site with the words "oil pump, high oil pressure, relief valve, oil relief valve" and a couple other variations have mostly pointed to head gasket issues, which I accept as a possibility.

I'm looking for any opinions regarding this situation. I haven't been driving it much since I got back to VT, maybe 100 miles total since the oil change. Figure it's time to start ordering parts and switch into tinker mode.

Thanks for any insight you can provide

-Dave

[Ace MM]

How much does the pressure increase?
How hot was the engine?

Do you see any oil in the coolant?
There are a few ways to rule out a bad head gasket, or confirm it.

[whatvan]

Ace,

I just have the stock dash gauges so I will be as specific as I can. I've attached a rare photo of everything running optimally for reference.

-The oil pressure, once increased, runs about half way between the two black lines on that gauge.

The oil pressure also seems a bit high at idle (just below the bottom black line) when the engine is first fired up and the engine idles at about 1000rpm for the first few minutes. I forgot to mention this in the above post

-The engine temperature does not increase greatly, but does increase. The needle for the engine temp stays just below the needle for the oil pressure. Similar to the photo, but higher on the gauge.

I'm not exactly sure what the coolant would look like with oil in it. After long drives it isn't quite so green anymore, but I haven't flushed the radiator, so I was thinking that it may be from corrosion in the radiator. Maybe oil is discoloring it though.

Since I'm looking for advice, I raise this question out of curiosity. Would a bad head gasket increase the oil pressure? I would have been under the assumption that something along those lines would decrease the pressure and some sort of blockage in the oil delivery system would increase it. But I have reached those conclusions through vague google searches, which is why I'm reaching out here.

Thanks again

[originalkwyjibo]

-The oil pressure, once increased, runs about half way between the two black lines on that gauge.

This is actually the normal range. I don't remember the exact spec and don't have a manual handy but this is the operating range I believe between 2-3000 rpm.

The oil pressure also seems a bit high at idle (just below the bottom black line) when the engine is first fired up and the engine idles at about 1000rpm for the first few minutes.

This would also be considered normal. The oil is thicker when it's cold which will increase the pressure as well as the slightly raised cold idle speed increasing it some too.

I'm not saying you don't possibly have an issue but your oil pressure seems good from what you describe.

[whatvan]

Thanks originalkwyjibo

I don't think it's a major problem yet, but maybe a symptom. In the 40,000mi I've owned it, the oil pressure has remained fairly steady on the lower black line. It's been the one constant since owning the van. Which is where my concern stems from. I'm really trying to minimize the odds of doing major repairs in the middle of nowhere Iowa or Montana.

I haven't been driving it much since the oil change. Took it for another drive today, same drive as last time. The oil pressure repeated my last experience on this drive, this time the coolant temp remained steady and low. However, last time, I spent the night at my destination and drove back in the morning. Today I stayed for about 30 minutes and turned around to drive back. The main difference was, on the way there it was warmer and dry. The drive back was raining and noticeably cooler.

On the drive back the gauges read steady, normal range consistently. None of this seems relevant or helpful. I'm going to keep driving it today and see if this keeps up.

[JPERL]

Recently, on a road trip from California to Vermont, I began experiencing higher than usual oil pressure.

I changed my oil before leaving Idaho for Cali. The van is an 89 4wd manual and has 161,000+mi. I was running 10W-40. Everything ran at optimal levels.

On the trip from Cali to Vermont, daytime temps were in the 90s and I was maintaining a speed of about 70mph (slower up big hills) at about 3000rpm. I drove a stretch of 1000 or so miles on the third day of the drive. I wasn't losing any more oil than normal, and I had run through some coolant. However, towards the end of this day I noticed the oil pressure had increased when the temps were up, but after sunset everything would run at acceptable levels.

Upon arrival in Vermont I changed the oil and filter. I opted for 10W-30 thinking that may be part of the issue. I drove about 50 miles after the oil change. The first 25 everything ran smoothly averaging about 40mph (50mph max speed) at 2500-3000rpm, but the second half of the drive the oil pressure increased.

My best guesses are possibly a faulty relief valve in the oil pump or a faulty head gasket (neither task I'm overly confident, or well prepared, to do myself).

Searching this site with the words "oil pump, high oil pressure, relief valve, oil relief valve" and a couple other variations have mostly pointed to head gasket issues, which I accept as a possibility.

I'm looking for any opinions regarding this situation. I haven't been driving it much since I got back to VT, maybe 100 miles total since the oil change. Figure it's time to start ordering parts and switch into tinker mode.

Thanks for any insight you can provide

-Dave

I owned these vans when they were new and actually that is on the low-normal side. At 2500 RPM for the first 100,000 miles the oil pressure gauge was always at the 2nd black line or slightly higher when cold and just a hair below the 2nd black line when warm using 10-40W. The oil pressure always stayed between the 1s and 2nd black lines even at idle and dipped slightly below in hot weather. This went for the 3Y and the 4Y

[Burntboot]

Another thing to consider is that the (factory) oil gauge is a representation of reality, its not reading actual oil pressure, there is a sender that converts oil pressure to an electrical signal, transmitted to the gauge on the dash which interprets the signal into a reading. They really are just a guideline at best.
The senders are notorious for failing, generally speaking the internal spring gets worn as they age they will slowly indicate lower and lower pressure, especially at idle. Dash gauges are also not known for their accuracy.

If the readings you're seeing are concerning to you, best to hook up a real oil pressure gauge (the kind that actually sample the oil pressure directly) to get actual readings and know wether there really is a problem or not.

It may also be worth checking all the electrical connections on the current system, a little corrosion/poor connection can effect whats displayed on the gauge.
BB

[spacelegovan]

I have not had this van long enough to know what the normal oil pressure is on the gauge but it seems very high this something to be worried about? The temperature gauge doesn't seem to get too hot at all but the pressure sure seems high, .... anything over 60 miles an hour and that gauge is way up there

[spacelegovan]

Hello? Anybody out there, I'm afraid to drive my van with this gauge acting like this, is the high pressure on the gauge normal at higher speeds.

[blakebecker37130]

Have you checked the actual oil level to see if its overfilled?

[VanCo]

In general higher oil pressure is better. When warm, off idle, It should be toward the top 3/4 mark on the gauge, in-between the two marks that delineate the acceptable range.

[spacelegovan]

Have you checked the actual oil level to see if its overfilled?

Thanx for the reply !! checked and its at full on the stick , up at 60 mph and above its pretty close to the H on the guage.....

[spacelegovan]

In general higher oil pressure is better. When warm, off idle, It should be toward the top 3/4 mark on the gauge, in-between the two marks that delineate the acceptable range.

Thanx for your reply, seems like its inbetween the 3/4 mark and the H

[Burntboot]

More is usually considered better but too much could be a problem, certainly not as bad as too little though.

As long as nothing silly has gone on such as thicker oil or a subgrade filter, it shouldn't be a problem.
Understanding of course that the factory senders and gauges are only indicators at best, they are not meant to be taken as gospel just to give an idea of how things are, when they're readings are out of spec it is important to investigate, after all, thats why they are there.
If the investigation proves fruitless then sometimes one has to look at the monitoring equipment.

Consider that oil pressure is converted to an electrical reading that is then sent too and displayed by the dash gauge as an interpretation of that electrical signal.
Having a corroded connection could very well cause a false reading, OP senders are notorious for causing issues, though usually they display low but....
For piece of mind, check with a real oil pressure gauge (lots of good threads about how to do that) and find out exactly what you're dealing with.
Always better to know for sure.

[spacelegovan]

Thank you sooo much Burntboot, ya put my mind at ease abit !