Caterpillar 3126B oil cooler problems

[hike]

Thank you @Keith Knight, and everyone else for thoughts and questions. While I would prefer not to do this you have pointed out that for some time and a couple hundred dollars this is a maintenance task level project.

Where did you find torque specifications and such? I recall having books on all our CAT equipment we used, though that was 30 years ago—

 

[hike]

Well the IFS filter is the real protection IMO, even thou I've not bought one yet. I'm Saving up lol..

The IFS is the high pressure filter on the HEUI output? Since I haven't kept up on this issue: filtering after the HEUI pump is better than before? or simply the best place to add a secondary filter?

Next question is for the time and money, isn't replacing the oil filter housing gasket best? Do we need secondary filter after replacing the gasket?

 

[Keith Knight]

On our 3126B we can’t put a filter before the HEUI pump so putting after protects the injectors and everything else after that. Basically preparing for the HEUI pump to fail. Replacing oil cooler and filter housing gaskets and if needed a flatter oil cooler or machining it flat what ever you decide. But the IFS kit is cheaper than replacing all the injectors. Replacing the HEUI pump is something that I could do on the side of the road if necessary. But replacing the HEUI pump and injectors on the side of the road not so doable. In my opinion.

 

[Keith Knight]

Thank you @Keith Knight, and everyone else for thoughts and questions. While I would prefer not to do this you have pointed out that for some time and a couple hundred dollars this is a maintenance task level project.

Where did you find torque specifications and such? I recall having books on all our CAT equipment we used, though that was 30 years ago—

I went with standard torque ratings for M8 bolts. For the filter housing and everything else is like alternator bolts and brackets I just tightened by feeling! LOL!!! Exhaust nuts tighten them really good too.
Also while I was working on it I discovered some soot near the exhaust manifold and block closest to the transmission. Turns out I had a loose exhaust manifold bolt.
Also found a missing bolt that holds the intake tube to the block. Just saying keeping a clean motor and looking for leaks or anything else on a regular basis prevents bigger problems in the future.

 

[GeneralDisorder]

The IFS is the high pressure filter on the HEUI output? Since I haven't kept up on this issue: filtering after the HEUI pump is better than before? or simply the best place to add a secondary filter?

Next question is for the time and money, isn't replacing the oil filter housing gasket best? Do we need secondary filter after replacing the gasket?

As with all engines - the main engine oil filter is not full flow. It is bypass filtration. So under MANY conditions the engine is already getting unfiltered oil. If the oil is cold, especially at high RPM (see ECO hub discussions), and if the filter element is partially plugged. If the differential pressure across the element exceeds the bypass spring rating in the filter head, it bypasses the filter on the principle that unfiltered oil is better than no oil at all.

The HEUI pre and post filters are FULL FLOW. In other words oil is not allowed to bypass them at all. Oil must flow through the filter or whatever is downstream from them receives insufficient oil.

 

[Ronmar]

Yea you could have a perfect oil filter and cooler assembly, but a HEUI pump failure is probably going to wipe the injectors also…

our main oil system actually has 2 bypasses in it. One pre-cooler, the other pre-filter..

 

[Keith Knight]

Thank you @Keith Knight, and everyone else for thoughts and questions. While I would prefer not to do this you have pointed out that for some time and a couple hundred dollars this is a maintenance task level project.

Where did you find torque specifications and such? I recall having books on all our CAT equipment we used, though that was 30 years ago—

I went with standard torque ratings for M8 bolts. For the filter housing and everything else is like alternator bolts and brackets I just tightened by feeling! LOL!!! Exhaust nuts tighten them really good too.
Also while I was working on it I discovered some soot near the exhaust manifold and block closest to the transmission. Turns out I had a loose exhaust manifold bolt.
Also found a missing bolt that holds the intake tube to the block. Just saying keeping a clean motor and looking for leaks or anything else on a regular basis prevents bigger problems in the future. The Gen 2 version has a filter indicator.

 

[Lostchain]

The HEUI pre and post filters are FULL FLOW. In other words oil is not allowed to bypass them at all. Oil must flow through the filter or whatever is downstream from them receives insufficient oil.

This post filtering (and the restriction that creates) is known to have absolutely no effect on the HEUI system? Is there any CAT documentation about this modification?

 

[GeneralDisorder]

This post filtering (and the restriction that creates) is known to have absolutely no effect on the HEUI system? Is there any CAT documentation about this modification?

The HEUI actuation pressure sensor is located in the cylinder head HEUI oil passage and if the filter system was some kind of restriction to flow it would cause a fault on the ECM as it tries to control pressure through the HEUI injection actuation pressure control solenoid on the HEUI pump. There is no documentation I'm aware of from CAT but the system is very popular on HEUI engines in lots of application - trucks, busses, RV's, and equipment. You can always call and talk to George the guy that makes them. Since the 3126 injectors are $1,000 each and this filter can prevent them from being contaminated by a pump failure.... you are looking at saving roughly $5k in the event of a HEUI pump failure.

That said - both of the 3216's I've worked with that had HEUI failures did not have the injectors replaced and they run just fine. Oil looked very clean in both situations and I have my theories as to what actually is going on (IE: HEUI pump isn't actually making a bunch of metal contamination and the failure is related to pressure regulation issues) but as yet have not confirmed the exact cause of these problems.