Ford Ranger Oil Pressure Gauge - Sludge?

I've recently been driving an old reengined 1986 Ford Ranger, I have no idea what the engine is, the truck says electronic ignition, but this looks conventional, 2.0 l or 2.3 l. The problem is the oil pressure gauge (it's the dummy variety - I tested it by grounding the sender wire - it reads slightly about half), goes straight up to good oil pressure, but then falls to zero after a few minutes, and stays pegged at zero, although the engines runs fine, although a little hot.

Is this an indication that I'm sludging at the oil pump intake port, or is it indicative of a stripped oil pump drive gear, or is the sender just bad. I don't want to put a new sender in, I don't even want to invest in a set of good gauges, but I don't want to blow the engine, and the alternative of dropping the oil pan and desludging it almost calls for basically removing the engine.

Anyone ever seen a sender unit fail like this, or do I have a deeper problem here.

Thanks!

Reply to
lifeform1
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More likely a bad connection or a bad sender.

Reply to
JimV

I think you have to find out if you have an "idiot light" type of sender or a sender that is built for a gauge. There is a difference and since you say it's been reengined, who knows what you have. To find out if you have a loss of oil pressure, you have to beg, borrow or steal a gauge to temporarily install, even if it's the cheapest one you can find. (And they do make cheap ones, too) This could be a bad sender, gauge or worn bearings.

Reply to
Kruse

The only time I've ever seen this is with excessive bearing clearance on mains and rods.

Reply to
F. H.

That's not promising. Would oil pressure go below 4.5 psi to trip the switch, but the engine still run fairly well? The problem is I've seen the gauge rise up once while I was driving, and the owner says he has occasionally has seen oil pressure go up, and water temperature go down, in lockstep, which to me indicates sludging or obstruction. On the other hand, it's an old engine, the water temperature does fluctuate with load or grade anyways.

Usually I have a lot of pressure gauges laying around, but this truck is either one of those 'get as many loads out of it as you can before it blows', or 'keep throwing good money after bad at it' types, and I can't be throwing money at it. I can either put any old accurate pressure gauge on it temporarily and try to get a reading down to the PSI, or I can buy a good dashboard set and wire those up, or I can just run it till it blows, but I don't want a new sender for an idiot gauge.

It's an ok truck, maybe I should just reengine it myself, because if I have to drop the oil pan, that's almost reengining. What kind of engines other than a 2.0 l or 2.3 l can go in here? How can I tell what I have?

Reply to
lifeform1

You obviously know it's just an idiot light disguised as a gauge, so you've got two states; on or off. If you think it's the sender (snap switch), just replace it. If it still does what you described, there's a real oil pressure problem.

Reply to
Sharon K. Cooke

He did find out and described how he did it. It's obviously a 'fooler'.

BUT if the sender is as big around as a small tomato paste can, it will send an erroneous LOW reading.. because of the dropping resistor in the gauge wiring. I assume that's not the case, because he gets NO reading... bet the sender is smaller than a half-dollar which means it's a switch.

Reply to
Backyard Mechanic

No, it's definitely an idiot sender. I haven't got an actual pressure gauge onto it yet, but I flushed the old synthetic out, and put in new conventional 5W-30 and drained it through, to try to flush anything out, and then put a new oil filter on, and now at least I have idiot pressure. I really don't think the sender is bad, and working under there, I noticed a ton of permatex or form-a-gasket or whatever, hanging down everywhere, the transmission pan, everything, and that has me very worried, if the mechanic who reengined it just slapped everything together, there may actually be some of that crap floating around in there. It's probably worth my while to rig up the most accurate under dash gauge that I can find, to keep an eye on it. I just don't want to blow $20 bucks on an idiot sender, but I suppose eventually I'm going to have to learn how to lift the engine and drop the pan. Possibly the engine and the frame aren't worth it, though.

I'm more interested in practicing a rational diagnosis, so I researched it all first, and then I thought I would bring it up here, since oil pressure is crucial. Thanks everybody!

Reply to
lifeform1

If I was concerned about possible bearing clearance I would lean toward heavier oil than 5-30.

Reply to
F. H.

That's good to know, thanks! At first I thought maybe the Castrol Syntec oil had perhaps desludged it out, knocking all the crap into the pan and fouling the screen, and I don't want to do a full blown engine flush on an old engine. That's a whole other discussion.

What I'm going to do is run this thin oil for a while, and I'm looking at a gauge set instead of a new sender. I really do think something is sticking onto the oil screen, but it could very well be a flaky sender. Then I'll get it hot and flush that oil out, and put in something heavier, certainly the engine could use it.

Thanks again!

Reply to
lifeform1

It may have been a sludging problem. I've used Mobil 1 mixed weights (w30 and w50) successfully in several cars including one with damaged mains. And if you dont hear thunking or tapping at a cold startup, you're probably okay.

I'd use Mobil 1, if oil use is low, rather than what you were using.. it will slowly eat all the sludge out and it's a pure synthetic, not just petroleum derived.

Reply to
Backyard Mechanic

What would be your take overall on changing (4.6 140K in excellent shape) that's been run on quality oil to something like Mobil 1? If you favor, what sequence would you follow? Filter changes etc.

Reply to
F. H.

On Wed, 12 Jul 2006 11:48:46 -0700, lifeform1 rearranged some electrons to form:

You might consider dropping the pan and checking the screen.

Reply to
David M

As in : i.e. - remove the engine. No thanks. That's too obvious.

So who designs these things where one critical failure path is inaccessible?

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Reply to
lifeform1

On Wed, 12 Jul 2006 18:10:40 -0700, lifeform1 rearranged some electrons to form:

I guess I missed the part where you had to remove the engine to take the oil pan off. That's not the case MOST of the time, but I'm not familiar with your particular setup.

Reply to
David M

I had an 88 Ranger with the 4 cyl engine (2.3l, IIRC) that I bought real cheap from a friend because it had no oil pressure and he didn't want to fool with it. The gauge read 0 and it was real noisy so it was pretty obvious that there was no oil pressure. According to the book, you could remove the pan by lifting the engine a little. I fought with it for a couple weeks trying to drop the pan then decided to hell with it and pulled the engine. It was actually fairly easy, took a lot less time than I had already pissed away trying to get the pan off. I removed the pan and found the pickup screen totally plugged with what looked like deteriorated gasket material. There was no sludge and it didn't look like there was any damage so I cleaned it up (that stuff was really packed in there), put it back together, re-installed the engine and it ran just fine...well, as well as an old Ranger with 140K miles could run. A couple weeks later, a guy saw it in the driveway and knocked on the door wanting to buy it...sold it for a tidy profit.

Anyway, sometimes pulling the engine is quicker than farting around trying to get to what you need to fix with the engine in...

Reply to
ZZ

, Autozone Duralast PS103 oil sender, $4.99 or PS222 for $6.99. Cheap mechanical gauge kit, $15.

If its running and not knocking, its probably a bad sender. 4 quarts of 30 weight oil., and a quart of marvel mystry oil, run for 15 - 20 minutes and oil change with 10-30 or 20-50 motor oil. Marvel is lot more gentle on seals then engine flushes. If you got a wrecking yard you can pull parts at, you might be able to find a gauge and plumbing for under $5.

The 2.0 had a carb, the 2.3 was fuel injected.

Whitelightning

Reply to
Whitelightning

Now you tell me. Thanks! My Autozone had kids working there, so I'll have to interrogate them now, I suppose.

It's making plenty of noises, but when you rev it up, it's fairly smooth.

I also hit a local Farm and Fleet too, and saw the Marvel stuff. I hear it's good for outboards too. The truck owner already got a bottle of Gunk, but that stuff scares me. When I'm ready for the heavy oil I'll definitely do a light flush. I know I basically ruined an old Ford Fairmont doing a full on engine flush once. I've always been stuck with

20 year old Fords. I remember an old Ford engineer used to say to me, for god's sake, don't change the oil! In those days, it seemed like that crap was the only thing holding the engine together. I want cryogenic fuel cells, but for now all I've got is old Fords.

Thanks!

Reply to
lifeform1

Dollars to donuts: 4 cyl fuel injected is going to be the 2.3. If it's carbureted it will be the 2.0.

I believe in '86 they had 3 engines available:

2.0 carbureted 2.3 EFI 2.9 V6 EFI

At a minimum the radiators and motor mounts are different from the 4 cyl to the 6 cyl. (fwiw, I've read that the radiator for a 6cyl is adequate for an

8cyl swap!). The front springs *might* be different between them, but I'm nto sure.

I've had an '87 2.3 EFI model and a 84 2.8 2bbl V6 (preEFI) and now a '91

2.9V6 EFI 4x4 (222K and still kickin'!)

If it's in any kind of shape otherwise, I'd say it's worth the effort.

~G~

Reply to
GMach3

Thanks! I've having a ball with it so far. I didn't get any respect around here at all until I started driving this old red truck! I'm hoping the engine will settle down now, and I can keep an eye on it too. It's getting to that hot part of the summer, and I'm pulling some huge loads with this thing. I've got some big Dunlop radials on it, slightly overinflated. It really bounces when it's light. The thing is hilarious, actually.

Reply to
lifeform1

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