13BT newbie, oil and cooling (1 Viewer)

[jblueridge]

I got my 88 BJ74 a few days ago and after checking the oil I was driving around in mud and fog having fun.

I noticed that the oil pressure registered towards low on the gauge and that the engine temp also showed low according to its gauge.

I searched old threads and have read that low oil pressure readings are common: I'm hoping that is true. I bought some Rotella oil and a cheap mechanical gauge to confirm oil pressure. Should I do anything else?

I also read that the cooling system thermostat opens to let coolant flow and in that position it blocks the flow elsewhere... where?

Thanks for any help.

 

[Oldtoy74]

The thermostat opens up once engine/ coolant has reached certain temp, either 82 d or ( 88' d for JDM's) once opens it flows through to radiator to be cooled down then back into block, thus reducing overall temp of engine / coolant.
Correct me if I misunderstood your question, but if the thermo get stuck open the flow continues through out the system resulting in engine not reaching optimal operating temp, if thermo is stuck closed, the engine will heat up and this should be visible on gauge, if not you may either cook your engine or blow a hose. Reduce the risk above by doing a new owners change over, standard surgery for a new JDM owner
Get your tools out order yourself a new thermostat and fit, check hoses get new ones if needed, new coolant, flush the radiator change the fluids in motor, box, and diffs, Cheap peace of mind
Any photos of your rig posted anywhere yet??

 

[jblueridge]

Misunderstood? Maybe.
I read and saw pics that showed the tall-ness of the thermostat and a photo of the inside of the t-stat housing seemed to be showing that the plunger of the opened t-stat blocked (for a good reason) a coolant passage. I'll look for the pics I saw yesterday.

Am I on the right track for the oil pressure?

I took some quick photos today and I'll get them up soon.

 

[RufusTheDufus]

You are correct about the thermostat. It's different than the typical American car thermostat. There's two sealing surfaces: one larger port that controls flow to the radiator and a smaller plunger-like feature at the bottom that seats in the housing. I don't recall the exact function of the bottom plunger but I think it influences flow through the heater core.

 

[roscoFJ73]

The oil pressure gauge is not the most accurate but generlly it sits about half way when hot and drop down to a 1/4 when idling. You can test it using a plug in pressure gauge and check the PSI against the figures in the manual

 

[jblueridge]

Thanks guys.
Right now, the oil pressure gauge sits at 1/4 while driving at speed. I don't like the look of that.

 

[watrob]

This is a synthetic oil your using, and in the older Toyota engines as they get old don't like synthetic oils. Synthetic oil get thinner as it gets hot where mineral based oils don't as much and as the oil heats and thins oil pressure drops away. Hence when first start your engine you have high oil pressure and as the engines heats up it drops back, it just drops back further when using synthetic.

You should, but depending on your climate be running a 15w 50 based oil if using synthetic., or one step heavier than what you running now. Its easy to do the test, next time buy a mineral oil of the same weight and you will see higher oil pressure.

And as the saying goes oils ain't oils, I am using a 20w60 (eqev to SAE30) high zinc content new generation oil (mineral based), but pouring it out of the bottle I could tell it flowed like 10w40, it felt like a very slippery oil due to the other additives.

But a general 15w50 mineral oil actually gives me a higher oil pressure and it did in the 2H as well.

Also a lot of these synthetic oils are high detergent based and yes they clean out your engine, they also start causing oil leaks. If you change your oil regularly you should not get a build up to begin with.

 

[RufusTheDufus]

This is a synthetic oil your using

Maybe Shell only sells synthetic Rotella in your area of the world but here in the USA they sell both regular mineral oil and a synthetic version. The 15w40 Rotella mineral oil is easily one of the most common/most popular oils for old diesels here.

 

[watrob]

Maybe Shell only sells synthetic Rotella in your area of the world but here in the USA they sell both regular mineral oil and a synthetic version. The 15w40 Rotella mineral oil is easily one of the most common/most popular oils for old diesels here.

Everyone here who talks about Rotella talks part or full synthetic. Here its all about the premium price you get for oils and it seems to be synthetic gets the higher price tag.

The general rule is that rebuilt engines you need a thicker oil as the clearances are larger than in a new engine from the factory. That's why companies make special running in oil for rebuilt engines with very high zinc content, not good for catalytic converters but then again old engines did not have them anyway?

 

[RufusTheDufus]

jblueridge - Where do you plan to connect your mechanical oil pressure gauge? I like to tap it into the oil feed going to the turbo if possible. Low oil pressure to the turbo can be hazardous to its health

 

[jblueridge]

First, full disclosure: I have never owned or worked on a diesel or turbo vehicle before. Rufus, can you point me to a photo or diagram?
I did not read the Rotella label carefully: I saw the words Diesel, 15W-50, and the salesgirl knew I would need about 7 quarts so I bought it.
Are the high-zinc fossil oils available just anywhere? I usually get Castrol for my F150.

 

[jblueridge]

Also, can someone check me out on the T-stat parts numbers? Looking for the higher temp. 88C (?)
I found these numbers:

Motorad = 286-82
Napa = Atm 1542401

 

[RufusTheDufus]

I did not read the Rotella label carefully: I saw the words Diesel, 15W-50..

I didn't know Rotella was available as a 15w50.

I'd recommend doing your own research on the necessity of zinc additives for your engine. I have no idea how it matters in relation to this topic whatsoever.

 

[Oldtoy74]

Thanks guys.
Right now, the oil pressure gauge sits at 1/4 while driving at speed. I don't like the look of that.

My oil pressure on gauge reads same as yours, ? I have ordered an adaptor in order check with mechanical gauge, just for my curiosity, I wouldn't say I'm overly concerned as the factory gauges generally are not that accurate.
On the lube subject, my last service I used a mineral 20/50, instead of 15/40, considering we were going into summer, the oil pressure in gauge has crept up a fraction while driving.

 

[jblueridge]

Oops! It IS 15w-40! It's this stuff

It has a reassuring image of a backhoe on it so it seemed right.

Saturday I'll look around on the engine for an easy place to plumb in the new mechanical gauge; hopefully near the turbo.

 

[Hulsty]

Mechanical gauge is the way to go, mine just goes where the original sender went. Using 15w-40 I normally have 60ish-90ish psi oil pressure.

 

[jblueridge]

Hulsty,
So your original oil press gauge is dead in the dash or did you put something else there?

 

[Hulsty]

Nah its dead, was like that when I bought it.

 

[carpet]

New sender from amayama trading from Japan was about 60 AUD. My gauge was reading low pressure but still responsive to rev changes, only it was reading very low. Changed the sender all good now on the factory gauge. It is a bit of a prick to change but doable! Couple of tools I used because I didn't have a claw socket

 

[jblueridge]

Thanks Carpet.
Quite an arsenal there.
Can't wait to wade into that.