6.5 Optimizer Oil leak, possible low pressure

[kontour]

Hello, new to the forum but there seems to be a lot of great info here.


I own a 1985 HJ75 that has been fitted with a 6.5 Optimizer running a turbo and intercooler. Purchased it already converted from the previous owner who estimated it had done around 70000kms.


Couple of questions, my oil pressure sits somewhere around 10-15psi at a hot idle and when cruising at approx. 2000rpm it sits around 30-35psi. Is this ok or does it indicate an issue?


The second question may be related as I have noticed a small oil leak from the intercooler plenum and when I pulled it off today it appears oil has been leaking from the plenum gaskets, however the inside of the intercooler and the rocker covers looks pretty clean.


https://imgur.com/GVUEftQ.jpg


Anyone have an idea what may be causing the oil leak? The bolts on the plenum were not torqued particularly tightly at all but I'm aware there really should be any oil on that side of the intake. There is an oil catch can fitted to the engine already.


Any ideas would be greatly appreciated as I've reached the limit of my knowledge on this. Thanks!

[DmaxMaverick]

Welcome aboard!

Your oil pressure is fine, and quite typical. I don't believe it to be related to a leak. Any leak that is associated with oil pressure drop would be a LOT of oil leakage, and you'd notice a lot more than a bit of seepage, anywhere.

I'm not understanding where from it's leaking. If the intake plumbing is clean inside, as it appears, the leak must be coming from somewhere else and is just accumulating there. The plenums aren't a source of fluid leakage, otherwise. The corrosion in the bolt holes look like they need some attention, though. The rubber gaskets require minimal torque to seal properly, but do require balanced torque to remain healthy over time.

By "oil catch can", do you mean the crankcase vents to atmosphere, rather than to the intake? That leaves the only place oil can be introduced into the intake would be from the turbo. If no oil residue is in the plumbing, then there should be no oil to leak out of it.

[kontour]

Welcome aboard!
By "oil catch can", do you mean the crankcase vents to atmosphere, rather than to the intake? That leaves the only place oil can be introduced into the intake would be from the turbo. If no oil residue is in the plumbing, then there should be no oil to leak out of it.

Thanks for the reply!


The crankcase still vents to the intake, but in between the PCV and the intake is a metal can that is designed to separate any oil out of the gas coming out of the crankcase, sending air back to the intake and hanging on to any oil.

Its probably been 1000kms since I last serviced the engine, so this has happened since then. I'm using a full synthetic 15w50 oil.

I'm having trouble working out where this oil is coming from, the main areas appear to be around the plenum gaskets, there was a little on the top of the plenum itself as well as a thin coating on the rear of both rocker covers with some build up in the v between them and the head. Also on closer inspection I've noticed a little bit in the V under the fuel pump, as well as a coating on the underside of the oil pan and the bell housing.

There is no other oil on the bottom of the intercooler, bonnet etc and the front of the block is clean too

The photo was taken after I'd hit the areas around the plenum with degreaser as I didn't want anything ending up in the intakes when I pulled it off.

If it was the turbo of a main seal or something I'd be expecting to see more oil around the turbo etc.


This has me stumped!

[DmaxMaverick]

What you describe sounds like a valve/rocker cover leak(s). It is the most common, and nothing else comes to mind at the moment. I suggest cleaning it up and watch it closely, often. The rear of the engine valley has a drain, so any accumulation of fluids there will drain down the back of the block and onto the rear pan and bell housing area. The valve covers are simply sealed with RTV (NO gaskets!). Many old and recent posts here on the procedure, but we can go over it again, if you need.

[DmaxMaverick]

Also....

Your "catch can" appears to be very effective. Much more than most, in my experience. Make sure it is not blocked and is venting freely. If not, it can allow higher crankcase pressure, leading to leaks (valve covers are most vulnerable). A properly operating CDR valve (PCV - the tuna can on the R/H valve cover) will maintain slight crankcase vacuum, which prevents most external leakage opportunities. If it's failed, it could explain the sudden leakage. I don't think any of this is related to the intake plenum.

[Robyn]

On most 6.5 turbo installs the CDR "TUNA CAN" vents to the air inlet close to the turbo inlet housing.

This creates the small vacuum needed to scavenge the crank case gases.

You mentioned that yours was vented to the intake ????

Can you post some pictures of the setup please ???

[kontour]

On most 6.5 turbo installs the CDR "TUNA CAN" vents to the air inlet close to the turbo inlet housing.

This creates the small vacuum needed to scavenge the crank case gases.

You mentioned that yours was vented to the intake ????

Can you post some pictures of the setup please ???

Sorry I mispoke, you're exactly right, it vents to the inlet after the filter.

https://imgur.com/LIYIAOt.jpg

Catch can is on the left, the bottom of it is plumbed back into the sump which is nice as it doesn't need to be emptied.

What you describe sounds like a valve/rocker cover leak(s). It is the most common, and nothing else comes to mind at the moment. I suggest cleaning it up and watch it closely, often. The rear of the engine valley has a drain, so any accumulation of fluids there will drain down the back of the block and onto the rear pan and bell housing area. The valve covers are simply sealed with RTV (NO gaskets!). Many old and recent posts here on the procedure, but we can go over it again, if you need.

I think you're probably right although I'm having trouble telling for sure. I managed to get a picture of the rear of the turbo housing.

https://imgur.com/0JqEvQG.jpg

Nothing too clear, but I'm not sure where else it could be coming from.

Got under the front and got a picture of the passenger side of the block, which also has oil on it. Obviously picked up a bit of muck from my last trip out bush.

https://imgur.com/WKeqqoz.jpg


Just also wanted to say thanks for the responses, these engines are not very common in Aus and as such there isn't a whole lot of knowledge about them. Can make diagnosing issues hard, but I'm glad there is such a wealth of knowledge available here.

[DmaxMaverick]

That's a tight fit, but looks like a nice conversion job. It appears the leak(s) have been present since before the last glow plug replacement. They look very recent. You may want to consider an OEM type harness for the plugs in the near future, with silicone wire insulators with ceramic connector insulators. Common primary wire and connectors will fail due to manifold heat over a short time.

[Robyn]

I always complained bitterly about the "tight" fit these engines have in the GM pickups and Burbs.

That is a snug fit in the Cruiser

My recommendation would be to warm the engine to JUST BARELY WARM then spray it down with some good engine wash/degreaser all over and hit it with the hose.

WARM it up good to dry it off and then run it and see if you can track down the origin of the oil leak.

Air blowing all over in the engine bay plus wind from the road and there is no good way to trace a small leak that's spreading itself about...

[kontour]

That's a tight fit, but looks like a nice conversion job. It appears the leak(s) have been present since before the last glow plug replacement. They look very recent. You may want to consider an OEM type harness for the plugs in the near future, with silicone wire insulators with ceramic connector insulators. Common primary wire and connectors will fail due to manifold heat over a short time.

Yeah i just did the glow plugs. When got the vehicle it had Diesel RX plugs in it which I don't trust as far as I can throw them and then I had a reason to change them as detailed below, so I replaced them with Bosch 80034.

Good call on the harness. When I replaced the plugs I realized that there was a significant amount of exposed wire where the spade connectors are crimped on. I'm not a fan of the whole glow system, there is no timing mechanism on it, just a 200A relay connected to a rocker switch in the cab. Not sure if the previous owner did it or it was part of the install.

Had a bit of a scare with the old plugs when the glow switch got stuck down and I didn't realize for a couple of minutes while driving. Was worried I would have tip swelling/ends breaking off but when I pulled them all the plugs were fine with the exception of the #1 Cylinder which had some carbon built up on it and needed some persuading.

[DmaxMaverick]

Yeah, what Robyn said.

Also, it looks more and more like typical valve cover seepage. If the engine (covers specifically) is/was original and untouched, they shouldn't be leaking, especially as uniform as it appears. If the covers were removed and resealed, they were likely done with gaskets, and the result is predictable. They should be sealed with RTV alone. Same for the oil pan. If done properly (like at the factory), they'll likely not leak before the covers are removed for other reasons.

[kontour]

I always complained bitterly about the "tight" fit these engines have in the GM pickups and Burbs.

That is a snug fit in the Cruiser

My recommendation would be to warm the engine to JUST BARELY WARM then spray it down with some good engine wash/degreaser all over and hit it with the hose.

WARM it up good to dry it off and then run it and see if you can track down the origin of the oil leak.

Air blowing all over in the engine bay plus wind from the road and there is no good way to trace a small leak that's spreading itself about...

It is a little tight, but luckily the vehicle is lifted, so between the bonnet access and underneath the front, most things are reasonably easy to get too.


I think you're right about the air spreading the oil, I would assume that the flow from the hood scoop + regular fan would create some interesting air flow patterns.

If I do need to get to the rocker covers to do the gaskets, do the intake manifolds have to be pulled as well, or can you get the injector lines out through the little gap they run through under the manifold?

[Robyn]

The intakes have to come off to get at the lines.

JUST AN FYI ON THE LINES

The lines should be fastened together in pairs with little rubber lined clamps.

KEEP THEM IN PAIRS
Tag the pairs before removal and make a little diagram of the injection pump and the line locations.

There are a couple that can be swapped and it just makes life really misserable.

A "CROW FOOT" ON A SHORT 3/8 DRIVE BREAKER BAR works sweet to get at some of the lines on the sides

A CAUTION

With the intakes off the ports are vulnerable to THINGS getting dropped/falling in.

DO NOT stuff rags into the ports.

A buddy of mine missed ONE RAG and fired the engine.

ENGINE WENT OOOOMPH, RAG WENT OOOOOMPH, BLOCK WENT BANG

Use Duct tape or some long strips of cardboard fitted so a couple of bolts can retain them.

The engine that got destroyed was a brand new block too...

The big thing on the valve covers is having all the surfaces flat and clean.

Clean the head surface well and degrease all mating surfaces with a suitable solvent such as BRAKLEEN.

Apply the high temp silicone so the entire channel area of the cover and around the bolts is about 3/16 to 1/4 deep.

Carefully sit the cover on the head and insert all the bolts.

Gently SNUG the bolts BARELY hand tight with a nut driver.

Allow silicone to cure for a day, then tighten the bolts up to spec (Snug with short wrench (1/4 drive ratchet and socket)

Make sure the cover flanges are flat with no bumps where bolts have been tightened up.

A flat piece of steel and a small hammer works sweet.

As Maverick mentioned, the gaskets just do not work on these engines.

Clean surfaces and the silicone goop is the trick fix.

Good luck

[kontour]

The intakes have to come off to get at the lines.
Clean surfaces and the silicone goop is the trick fix.
Good luck

Wow great advice, thanks heaps!

Just out of curiosity I have read in a few places that Permatex "The Right
Stuff" is the best gasket maker to use for this application, is this correct?

Also another unrelated question, my truck came fitted with an oil cooler when I bought it, but whoever made it had no idea what they were doing. It's essentially an old bit of intercooler with some fittings welded on the end which was then mounted to the bottom of the bull bar with no shock absorption. Over time the core has cracked and started leaking, and when I pulled it off the bull bar the fitting on the output sheared off to reveal that there wasnt even a plate in the cooler between the input and output.

My question is if i should fit a new one? I’ve currently just got a bypass fitting on the ends of the lines.

As I understand it the sump volume on these engines is quite small and here in Aus they are well known for having over heating issues, possibly due to our climate. Obviously the extra sump volume isn't going to hurt, but will the oil be running too cool if I install another cooler? As I understand it the oil needs to hit certain temps before additives activate as well as boiling off condensation.

Obviously this is hard to gauge without installing the cooler and measuring the temps, but I'm wondering if anyone has had any experience with external coolers on the 6.5.

[sctrailrider]

Don't use a sealer on the intake, the gasket is plenty good enough and easier the next time you need to remove it. The right stuff is great for other places, valve covers, oil pans, etc... places you don't need to remove often..



I guess if the oil cooler isn't leaking and the lines are good then it will be OK... if the cooler lines are the stock type with the clips holding the lines to the block fittings then replace the lines with a better kind that don't use the clips.. they often fail..

[DmaxMaverick]

Yes, the intake gets gaskets. The Right Stuff is a premium RTV. It is better than traditional RTV (silicone gasket maker), IMO. I like the "Cheese Wiz" can version. It's just too easy, but costs a little more per application (worth it!) than the traditional squeeze tube. One can will do both valve covers or the oil pan, but you'll need 2 cans for both. I can be had in calk-gun tubes for higher volume needs, as well. It can be used for timing cover and water pump installations, but traditional RTV does that job just as well.

On the oil cooler.....
Don't run without one! The engine oil gets HOT, and must be externally cooled. The radiator tank cooler is a bare minimum, and inadequate in almost any condition beyond a grocery-getter, especially in any severe environment such as yours (and mine). You really can't overdo it (no such thing as too cool). The engine oil cooler circuit is between the oil pump and gallery. The oil going through the cooling circuit has already been through the engine and collects in the sump. Any heat needed for moisture control or "heat activation" (if that's a real thing) will happen in the engine before it hits the cooler. Proper installation of an effective cooler is necessary for durability. Bigger is better, as space and resources allows. Don't skimp on the external cooler lines, either. They are a weakness, and the most common point of failure, leading to catastrophic engine damage. The OEM lines are marginally adequate, and don't last long.

[kontour]

Yes, the intake gets gaskets. The Right Stuff is a premium RTV. It is better than traditional RTV (silicone gasket maker), IMO. I like the "Cheese Wiz" can version. It's just too easy, but costs a little more per application (worth it!) than the traditional squeeze tube. One can will do both valve covers or the oil pan, but you'll need 2 cans for both. I can be had in calk-gun tubes for higher volume needs, as well. It can be used for timing cover and water pump installations, but traditional RTV does that job just as well.

On the oil cooler.....
Don't run without one! The engine oil gets HOT, and must be externally cooled. The radiator tank cooler is a bare minimum, and inadequate in almost any condition beyond a grocery-getter, especially in any severe environment such as yours (and mine). You really can't overdo it (no such thing as too cool). The engine oil cooler circuit is between the oil pump and gallery. The oil going through the cooling circuit has already been through the engine and collects in the sump. Any heat needed for moisture control or "heat activation" (if that's a real thing) will happen in the engine before it hits the cooler. Proper installation of an effective cooler is necessary for durability. Bigger is better, as space and resources allows. Don't skimp on the external cooler lines, either. They are a weakness, and the most common point of failure, leading to catastrophic engine damage. The OEM lines are marginally adequate, and don't last long.

This is very interesting. Most of the Optimizers used for conversions here are installed without oil coolers as far as I know. I wonder if this has any relation to the reputation they have for over-heating in Aus. Much has been made of water system upgrades over here, but I don't know how much has been done on the oil cooler side of things.

The cooler that was installed on it (picture here) was pretty big: 22" x 4.5" (actual width of the core is more like 2.5") x 4.7" and I'm having trouble finding a direct replacement. The closest I can come is this or at significantly more expense this, which is shorter than the first.

The lines have been upgraded to fairly heavy duty hose, I think it was the unsupported weight of the lines along with the vibrations over time that caused the fitting on the cooler to shear off when I was removing it. I'll be remedying that when I install the new cooler.

[DmaxMaverick]

I can't imagine any 6.2/6.5, or any Diesel running w/o an oil cooler.The thought never occurred to me. The Duramax, for example, has 2 (engine integrated coolant-oil, and external air-oil). Heat management would likely be an issue without one, let alone oil life concerns. Either of the coolers you linked appear to be at least adequate, and certainly better than nothing. They don't have to be complicated or expensive, only effective.

[Robyn]

I agree 100% on the oil cooler subject.
I have seen several OEM lines go away... UGLY...

Use the stainless braided type lines that are rated for the job.

Mount the cooler in a place that it can live and get good airflow.

[Yukon6.2]

Any reason you can't have your cooler fixed,and strengthened.
It fits were it was designed for,seemed to be working.