Oil pressure super high on highway

[dan01d]

Hi all. New here and looking for advice/ info on my oil pressure guage on the dash of my 80 series. Usually sits pretty low about a third of the way up but today after 30mins on the highway it shot right up to the top of the guage it was not gradual just shot up. Then back off the highway it went back down. Put some oil in and it was ok gor a little while then shot up again at 100ks. Dropped off the 80 or 90ks and it went down again.
So im looking for peace of mind or advice. Thanks in advance.

 

[Chris]

Personally I'd ignore it. All that gauge does is cause people grief. The best it does really is say well there's pressure of some sort but that's it. I had one that read zero and I left it like that. Never missed it.

You can test the oil pressure with a proper gauge for peace of mind. You can change the sender unit too, they're cheap and you'll probably get an entirely different reading that causes you even more confusion. Sounds like an electrical problem to me. Not sure if there is a relief valve in there anywhere that's causing an actual problem.

But odds are it's just the sender. Get it tested. I have a kit from Machine Mart or somewhere that just screws into the sender unit.

 

[nick_the_fish]

Agree with Chris. I've had problems with my oil pressure gauge peridocally bouncing around for years now. For all the solid engineering Toyota put into Land Cruisers they somehow managed an epic fail on the oil pressure gauges.

Personally i'm going to replace my sender unit/ cabling and gauge with a new (non-toyota) system.

 

[frank rabbets]

There's a pressure relief valve in the system and in fact all engines I've worked on. They can fail but usually lead to low pressure. I've never known one failed and stuck in the seated position which might lead to high oil pressure.

Check with a mechanical gauge. I found that 1/4 BSP thread fitted my block but I don't know if that is the correct definitive thread size.

 

[clivehorridge]

All the above... the dash gauge on my 80 decided to zero itself and stayed there. So I bought a medium priced pod gauge, with its own (electrical) sender and that gives me peace of mind.

Oddly its calibrated in BAR and goes up to 10 BAR, not much use in an 80, I get 1 BAR on idle and about 4 BAR max cold at highway speeds that drops to about 3.5 BAR when warm.

Suits me, at least there is some pressure, whatever it is.

 

[IRLGW]

As clive has touched on Warm v Cold makes a difference. When its cold expect to see higher reading. Low oil level wouldn't cause high pressure so topping it up wouldn't have any effect on that symptom. Maybe change the oil filter and see if that helps.

 

[AndycruiserguyLomas]

Hi all. New here and looking for advice/ info on my oil pressure guage on the dash of my 80 series. Usually sits pretty low about a third of the way up but today after 30mins on the highway it shot right up to the top of the guage it was not gradual just shot up. Then back off the highway it went back down. Put some oil in and it was ok gor a little while then shot up again at 100ks. Dropped off the 80 or 90ks and it went down again.
So im looking for peace of mind or advice. Thanks in advance.

As Chris says,ignore. Now if the warning light ( for low oil pressure) comes on, don't ignore. on 60 series there was a device which cut the fuel if the oil pressure was low for a short time to save engine damage. I don't know why they don't fit them these days.
They don't put then on modern Landcruisers for a reason.

 

[Chris]

Correct Frank. 1/4 bsp thread. Though I think it might be bspt (tapered)

 

[chapel gate]

I have a couple of 80s where the gauge instantly shoots to the high position once the engine is started.

 

[frank rabbets]

Chris I don't know if the block thread is tapered or not but yes a tapered male 1/4 BSPT saves you possibly needing a washer for sealing and again the block may not be flushed off to take a sealing washer.

Bit of a mystery threads. I went round a big hardware store in Spain where their copper pipes were metric but their bigger threaded steel pipes were clearly stamped in inches and fractions.

 

[flint]

A hangover from when British engineering ruled the waves ? A bit of an explanation here: https://journeymans-workshop.uk/bspthreads.php

 

[frank rabbets]

I would think a hangover yes but I wonder why Europe mainland uses metric for copper pipes. Perhaps they were never imperial there.

 

[flint]

I think you're right, in fairly modern times at least, they always were metric. Copper pipe (in France at least) is sold in different sizes compared to the UK, usually the size being given as two numbers, the internal and external diameters in mms. In the UK the metric size (introduced in about the 70s I think) is roughly the equivalent of the old imperial measurements, so linking old to new is easier (if you’ve got the right olives !).
It looks like things took off for BSW (and BSP) after the building of several gunships for use in the Crimea went down well with many major powers taking notice and also down it being adopted by machinery manufacturers and the railways, British products being widely exported. (https://en.wikipedia.org/wiki/British_Standard_Whitworth ) The ISO metric thread standards were not introduced until the late 1940s, so I suppose that by this time BSP was so well established in plumbing, they stuck with it.

 

[frank rabbets]

I think I need a degree to understand all that !!

I have always wondered why BSF bolts have smaller head sizes than their equivalent shank diameter BSW bolts. Was it really to save material?

 

[flint]

After a bit of reading various websites, it seems that the one size head and nut difference between the two was that, with its finer thread the BSF had a mechanical advantage over BSW so the head size was reduced to limit the effects of over tightening (shorter spanner lengths). Just to add to the fun, during WW2, the head size of BSW was reduced to that of BSF, probably to save steel . Discussed here: http://www.triple-mregister.org/forums/topic.asp?TOPIC_ID=14366 and here:http://www.baconsdozen.co.uk/tools/conversion charts.htm I like metric !

 

[Dave2000]

The senders are a bit flaky as they wear, but they are adjustable. It is a simple job to calibrate although a little time consuming. I calibrated mine around six years back, it has worked perfect since.

Regards

Dave

 

[frank rabbets]

Connectors also get loose/corroded. I cleaned and bent mine, covered them in grease and they have never given a problem. That's assuming I have oil pressure lol.