High oil pressure

[AMiller320]

So now that the 88 GrandWag runs (and stays running), it's time to tackle some other issues...

What does it mean when I'm showing high oil pressure?

As soon as I start up, it shoot to about 70-80 psi. The oil level is good, and the oil is clean. Truck runs/drives fine as far as I can tell. The fuel gauge is whacked, so it's possible that it's a bum gauge. I plan on getting a pressue gauge so I can check it under the hood soon. But, any thoughts on what that might be?

Also -- what color should brake fluid be in the truck? Dark or light?

Thanks!

[woodybeone]

What pressure do you have at highway speed when warm and at idle when warm ?

[joe]

<BLOCKQUOTE>quote:</font><HR>Originally posted by AMiller320:
Also -- what color should brake fluid be in the truck? Dark or light?

Thanks!<HR></BLOCKQUOTE>


It should be clear.

[Shane]

Your brake fluid when it came out of the container would have been "light", but as it absorbs moisture and impurities it darkens.

It may be a good idea to flush and refill the system.

Shane

[AMiller320]

The oil pressure stays between 70-80 psi all the time... at idle and at freeway speeds. It only drops a bit when I let off the gas, then it climbs again.

Yep, time to flush the fluid. It looks like black ink.

[jeepbob]

The gauge is wacked right out of its mind, either get a new gage/sending unit or put in a mechanical gauge. There is no such thing as an AMC motor with too much oil pressure.

[andy d]

i read your post and said to myself 88 wag. yup, the sending unit is toast. mine was reading a constant 80lbs, actual pressure was a lot nearer 0. they changed the sending units about the same time they did the dashboard change. there are a few other things they changed that werent so hot either.

[Lindel]

They changed the gauges the same time they changed the senders, also the same time they changed the dash.

"late" model FSJ's (86 and newer) only had gauges for entertainment on those long trips. The oil pressure gauge is the comedian of the bunch.

Try the sender first (it's relatively cheap), if that doesn't work, install a mechanical (but be very careful of the nylon tubing, to make sure it doesn't chafe on anything, or doesn't get nicked in the install process. If you don't, you'll find out why they don't install mechanical gauges in cars, these days).

[Joe's 89]

&gt;&gt;"late" model FSJ's (86 and newer) only had gauges for entertainment on those long trips. The oil pressure gauge is the comedian of the bunch.&lt;&lt;&lt;

That's the best one I have heard lately!

[64Trvlr]

<BLOCKQUOTE>quote:</font><HR>Originally posted by AMiller320:
What does it mean when I'm showing high oil pressure? As soon as I start up, it shoot to about 70-80 psi.<HR></BLOCKQUOTE>

ROTFLMAO
This is amazing, I've NEVER seen the words high oil pressure and FSJ used together before.
:cool:

[jeepbob]

Rather than use that nylon tubing, you can for a few dollars more, get the copper line kit. The copper line is much better to use than the nylon due to closeness of the exhaust manifold. Be sure to use "P" clips to hold the line to the oil pan to cut down on the vibrations that can cause copper to work harden and crack.
For those of you with cubic dollars ( I used to race against guys like you) there is always the steel braided line kit. I think Summit carries them.

[64Trvlr]

<BLOCKQUOTE>quote:</font><HR>Originally posted by jeepbob:
Rather than use that nylon tubing, you can for a few dollars more, get the copper line kit. The copper line is much better to use than the nylon <HR></BLOCKQUOTE>

Another thing to do is put a loop in the line before you run it through the firewall. That will help the line to live a long and happy life.
:cool:

[Darin]

I experience the same oil pressure readings as AMiller320, and though I agree with everones reply for the most part I thought I would add a couple things.

1. when i bought the 89 GW the guage was pegged (above 80). found a short in the sending wire and fixed it.

2. the new readings were 45 at best and high 20's at worst.

3. had to replace the rear main seal, and after cleaning everything out in the pan and inspecting - all was well- it went up to 65-70 at best, and never below 50. the guage seemed very accurate.

4. after last change, I added some conditioner to the usual valvoline 10-40 (forgot the name of the stuff) and it boosted another 5- 10 lbs.

5. i replaced the sending unit just to be sure, but the guage seems accurate. or i want to think that it is.

So what i am hearing is that my well maintained, stock 360 with 115 miles on it can't have pressure this good?

[Lindel]

I never said that a FSJ can't have good oil pressure, but there is great doubt in the gauge's ability to tell anything accurate!!

In a lot of cases, there's great doubt in the gauge's ability to tell you anything of ANY value.

The older FSJ's, for the most part had Stewart Warner gauges, and those seem to be a lot more steady, and accurate.

[AMiller320]

Hey, everyone... thanks for all of the feedback!

My plan is to test the pressure manually, and assuming it's okay, I'll just start ignoring the gauge. There are too many other things that need attention first!

Thanks again -
Andy&gt;&gt;

[jeepbob]

While it is possible for a new AMC motor to have up to 70 psi (this is the max that the relief valve is set for) the reality of it is that AMC oiling systems s*ck and it will not stay there for long. But do not fear as they usually have 45 psi for tens of thousands of miles.