Low oil pressure, after overheating

[Isuzusweet]

IMHO

I think previous posters have hit the mark with 5W being way too light an oil, especially in heat and old motors and yet if you read the link below it will state something different.

IMHO, staying with 10W-30 should do the trick. If temps were over 90F I may think of going to SAE 30 oil but a modern 10W-30 should be able to handle the heat.

It's always a toss up when or if to turn to synthetic oils. In more modern engines with dual cams, smaller cooling systems and tight tolerances, it's a no brainer, synthetic all the way. In the older engines it's a different ballgame with seals that have difficulty sealing against synthetic (leaks) and a few other reasons already stated in this thread; thusly staying with fossil oil is a better bet.

You should read this.....

http://www.upmpg.com/tech_articles/motoroil_viscosity/

I think you dodged a bullet, but gained a lot of knowledge; a win, win.Heck even I learn a new trick or two.

Cheers
Tony

PS I run synthetic in my 2.5 V6 Tracker and 3.5 V6 Altima but dino juice in my Jaguar XJS and Airstream 310 turbo diesel.

[slowmover]

Converted my Dads 1987 Suburban TBI 454 to Mobil One 5W-50 synthetic with about 160k on motor roughly twenty years ago. Oil use dropped and stabilized. He ran truck to 190k. That truck pulled his 8K lb 28' Silver Streak for fifteen years. A 15k combo.

I'd use Rotella T6 5W-40 in that truck today, or if I still had my old 440-V8 Chrysler sedan. Donaldson (Stratapore) or Baldwin filters, only.

FWIW, I severely overheated that big Dodge one night and kept going. Miles and miles. One dangerous part of town. Let it cool for several hours. Made it home after putting water in. Next day, replaced failed water pump and changed oil (M1 5-50). Drove it for another few years. Nothing noticeable. I've rebuilt a few engines along the way. This one didn't need it, but it was far from fresh (original, actually).

Good luck.

[Grosspoluter]

Good news
I got the oil sample report email today and although they say it's kind of a short (engine not run long enough) sample it all looks GOOD!!!!!!!
I have Mobil 15/50 sitting in the engine now, with a wix filter
I've taken it on two short runs 5-8 miles with... Ok results...
Only got it up to 45mph...
I'm thinking this weekend if I get the chance, I'll take it for a little longer drive and up to 60-70 mph (baby steps)

[bkahler]

Originally Posted by Grosspoluter

Good news
I got the oil sample report email today and although they say it's kind of a short (engine not run long enough) sample it all looks GOOD!!!!!!!
I have Mobil 15/50 sitting in the engine now, with a wix filter
I've taken it on two short runs 5-8 miles with... Ok results...
Only got it up to 45mph...
I'm thinking this weekend if I get the chance, I'll take it for a little longer drive and up to 60-70 mph (baby steps)

Looking forward to hearing out the 60-70 mph run goes

[Grosspoluter]

Ok so I braved the highway for 5 miles at operating temps
Still no bad noises
BUT before the overheating my operating temps were....
Outside temp 85, coolant 168, oil temp 215, oil pres 63, 70 mph, 3200 rpm's
Today it was much cooler outside and was even misting outside when I went out to do my short run so this is what I got for readings (oil and coolant temps were warmer)
Outside temp 75, coolant 186, oil temp 225 oil pres 49, 70 mph, 3200 rpms
Keep,in mind I the first readings were using 5W30 oil the current readings were using 15W50.
I should also note that when speed and rpm's went down the oil temp actually went down considerably form 225 to about 211
Seeing how coolant and oil temp were up I'm thinking air flow, more specifically (maybe) fan!? The thing is though I'm sure the clutch fan is working I can here it "kick" in when coolant reaches about 210-220
Does thicker oil run hotter?
I admittedly am horrible at math, but I believe both the temp differences are (average) 25% hotter?
I'm afraid I'm entering Physics here, and may be over thinking everything?
Any thoughts?

[Waipio Rim]

Unless you are willing to adopt my "drive it until the wheels fall off" philosophy, I think that the best advice that you have gotten here was in posts #21 and #36: pull pan, replace pump, check bypass spring. This would be new territory in wrenching for me, but would probably not be an expensive job for a shop to do.

[TomKirk]

Originally Posted by Waipio Rim

.....I think that the best advice that you have gotten here was in posts #21 and #36: pull pan, replace pump, check bypass spring.

If you pull the pan, you should take it to the next level; pull bearing caps and inspect rod and main bearings. Granted, you may not find anything, but at least you'll have peace of mind about lower end damage. While you're at it, do a plasti-gauge test for wear.

Also: 15W-40 oil is for diesels. If you're thinking about a heavier oil, use 20W-50 instead.

As the lab stated, oil test validity is compromised. Crankcase "residence time" (as in miles driven) is a critical component of the test. Do a second test. This time, follow directions. The last thing you need is engine trouble on the road.

BTW - 5W-30 oil didn't really come into popular use until the early to mid 2000's when engine tolerances became much tighter. More importantly, oil circulation was based more upon flow volume (as in quarts per minute) rather than PSI. And yes, fuel economy was a "bragging factor" in this change.

Tom

[Bill M.]

I can see no reason not to pull, or have pulled, the pan and check the oil pump and the pickup. Unless perhaps you have to remove the engine to pull the oil pan? You know the oil pressure has gone down markedly. You did not drive it far. I would think it is most probably the low oil pressure problem is on the supply side. And while you are there you can check the rod bearings.

[Kota]

Oil removes a fair amount of heat from the engine. Lower oil pressure would lead to a lower flow rate. Especially important under higher loads. I would still suspect the pump or a bearing. Possibly a cam bearing. The bypass spring is a regulation device that maintains a set oil pressure as rpms increase. It's a pretty crude regulator but should maintain a reasonably stable top pressure as the engine wears, temp changes...

It really isn't a bad job to pull it if you can get under it and they haven't blocked it with an axle, crossmember, exhaust... Never been under one. The pump is easy to pull and replace. I'd leave the rod and main caps to a shop. If you DIY inspect and torque them one at a time. Don't unseat the bearing from the cap and maintain correct orientation. Check the surfaces for galling, scratches, discoloration. Any damage would generally be transmitted all around the journal os you don't have to rotate the engine. You can use plastigauge to check the clearances. Plenty of info on that on the Internet. I've seen some pretty torn up bearings that were not making noise or producing much metal.

It is possible that the low oil pressure lead to the overheat.

[tjdonahoe]

15-40 oil will work fine, been using it for years in gas engines, I believe your oil pressure starts with the cam bearings...

[Grosspoluter]

Any thoughts on what oil pump I should go for
Stock, high volume, high pressure?
I would think a high volume pump would be better, just because of the engine size (more volume of oil in block) and because of the external oil cooler.

[Grosspoluter]

I have not pulled the pan or pump... Yet

[Grosspoluter]

I really can't pull the pan where the RV sits now at a storage place
And the place it's stored at is about 50 miles from my house...
If the RV was at my house I could pull the pan and pump pretty easily. I've looked under the RV and there looks to be plenty of room to drop the pan and all f the pan bolts (except for 2) all look really easy to get to
Just a little Leary of driving it to my house in its current condition😟

[J. Morgan]

Just drive it watchfully for a time till you regain confidence.

I have rebuilt over a dozen Chevy big blocks, out of these I have seen one failure of an oil pump caused by the pump ingesting pieces of a fiber timing set.

This failure resulted in the pump shaft breaking where the pump drive shaft entered the pump. This means zero oil pressure, not a reduced flow.

An oil pump is one of those things that is seen as easy to change, and therefore a lot of good ones are replaced.

While your oil pressureREADS lower than it did, it is still within spec.

There MAY be some bearing damage, but in light that there are no knocks, my advise is outlined in the first sentence of this post.

Join Good Sam or AAA, get free towing, and test it for a few trips close by. You will either;

A. Find that there is a real problem

or;

B. Find that there is little to nothing to worry about.


Gradiens super tenui glacie.

[J. Morgan]

I have in my youth "fixed" things because I "think" something is wrong, this never really worked out.

Most of the instances can fit into two results;

A. Nothing was wrong

B. What was wrong was more major than my "fix".

In both cases the time spent on the "fix" was wasted time, money, and effort.

Addendum;

A plugged oil pump pickup screen has its own symptoms.

Usually;;; initially oil pressure is good upon start up, but decays as you drive and/or bring the engine RPM up.

The pressure will fall to near zero.

If the engine is turned off for a few minutes, and then restarted, the pressure is good again, until the debris is drawn back against the screen.

This seldom happens on older engines with large oil pick up screens, but is quite common on more modern engines that are equipped with small and tightly woven pickup screens.




Gradiens super tenui glacie.

[J. Morgan]

Modern engines use an oil pump pick up that offers about 1/3 the screen surface area of a pick up found on an older engine like a 454.

It would take a lot of trash to plug up a 454 oil pick up. Not impossible, just improbable. This issue is much more likely on newer vehicles.


Gradiens super tenui glacie.

[Grosspoluter]

So then I doubt it's the pick up because the oil pressure stays low when the engine is at operating temp
Even when I did the oil changes, when the engine was warm, when the "cool" oil was in, and engine started the pressure would come up a little maybe from 15 up to 20 but not like the 60psi when it's cold!

[TG Twinkie]

I don't know how many miles or hours of operation this engine has.
It is over 30 years old. If I had the kind of oil pressure readings you are getting I would keep driving.

[Grosspoluter]

I've taken the RV on a few short 5 to 6 mile highway trips
oil temperature and pressure still seems to be a little high in the temperature side and Low on the pressure side
I am wondering what to expect when I pull the oil pump.
I did a oil pump on a ford FE engine and the oil pump is run by the distributor is that the way it is on this for the 454, and I'd like to ask again on any thoughts about the oil pump replacement should I use a high volume pump or a high-pressure pump? Will I need to prime the pump before or after I put it on ? If so how do I do that?
If I do get the nerve to take it home and drop the pan and replaced the pump, I will definitely get another oil analyst done

[tjdonahoe]

I would pull the pan and check the mains and rod bearings, a new oil pump won't help if bearings are worn....