Hey guys I have a coolant leak from my 4BT and am convinced it’s my freeze plug , but I wanted to do my due diligence first before pulling the trans and T case to make sure that’s what it is . There’s coolant leaking from the bell housing cover dripping down to my sway bar and trans . No other obvious leaks . And unfortunately no access to the rear freeze plug due to the AA adapter to my 4L85E trans…. Anyone have the Cummins # for the rear freeze plug or pictures so I can see what I’m working with , couldn’t find anything on the web.
Mystery coolant leak
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Only other place might be the rear location on the left side of the head for a temp sender. If it is the head you might look at my post about my head bolt failure. Best to go back with studs and make sure to get a quality gasket. Pressurize your system at the radiator and let it sit cold. Should help you find out for sure where the coolant is coming from. Jmtcw
The one near the top of the block is covered by the Advanced adapters adapter plate , it’s very large , but based on what I saw , it’s leaking behind cylinder 4, not very happy about this, seems like it’s been one thing after another unfortunately
not sure why it would have cracked , but I’ll get the head checked when I pull it off .
Cummins has a lower engine gasket kit which is part 3802375 which sells for $519.10. That is every gasket and seal below the head. That is a complete rebuild kit. The head gasket and exhaust gaskets are not included in that kit. Standard head gasket is part 3283333 (.25mm oversize is 3283336 and .50mm oversize is 3283338), valve cover gasket 3930906, oil filler cap gasket is 3936876, intake manifold gasket is 3938153, aftercooler inlet gasket is 3914856, exhaust manifold gasket is 3927154, turbo inlet gasket is 3709861, and turbo oil drain gasket is 3765575. All the gaskets and seals in that big kit can also be bought individually. There are 38 different parts in that kit. There are 2 different filter head gaskets in the kit depending on which block arrangement you have. Early engine types use gasket 3929792 shown here.
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Later engines use gasket 3942915 shown here.
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Here are all the gaskets in the big kit.
Parts Catalog
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Have fun.
Later engines use gasket 3942915 shown here.
Here are all the gaskets in the big kit.
Parts Catalog
| Ref | Part Number | Description | Quantity | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3802375 | LOWER ENGINE GASKET SET | 0 | ||||||||||||||||||
| 1 | 3283767 | PUSH ROD COVER GASKET | 1 | |||||||||||||||||
| 3901020 | PISTON COOLING NOZZLE | 4 | ||||||||||||||||||
| 2 | 3902425 | SEALING WASHER | 2 | |||||||||||||||||
| 3 | 3903475 | RECTANGULAR RING SEAL | 1 | |||||||||||||||||
| 3905595 | TIMING PIN HOUSING GASKET | 1 | ||||||||||||||||||
| 4 | 3906696 | RECTANGULAR RING SEAL | 1 | |||||||||||||||||
| 5 | 3906697 | RECTANGULAR RING SEAL | 1 | |||||||||||||||||
| 6 | 3906698 | RECTANGULAR RING SEAL | 1 | |||||||||||||||||
| 7 | 3908096 | COVER PLATE GASKET | 1 | |||||||||||||||||
| 8 | 3912473 | RECTANGULAR RING SEAL | 1 | |||||||||||||||||
| 9 | 3913994 | O RING SEAL | 1 | |||||||||||||||||
| 10 | 3914385 | GEAR COVER GASKET | 1 | |||||||||||||||||
| 11 | 3915772 | RECTANGULAR RING SEAL | 1 | |||||||||||||||||
| 3915800 | RECTANGULAR RING SEAL | 1 | ||||||||||||||||||
| 12 | 3916042 | HYDRAULIC PUMP GASKET | 1 | |||||||||||||||||
| 13 | 3920773 | SEALING WASHER | 1 | |||||||||||||||||
| 14 | 3928759 | GROMMET SEAL | 6 | |||||||||||||||||
| 15 | 3929751 | ACCESSORY DRIVE COVER GASKET | 1 | |||||||||||||||||
| 16 | 3929792 | FILTER HEAD GASKET | 1 | |||||||||||||||||
| 17 | 3933261 | DUST SHIELD | 1 | |||||||||||||||||
| 3934486 | RR CRANKSEAL SERV KIT | 1 |
| |||||||||||||||||
| 3937111 | FRONT SEAL SERVICE KIT | 1 |
| |||||||||||||||||
| 20 | 3937214 | PISTON COOLING NOZZLE | 4 | |||||||||||||||||
| 21 | 3938156 | GEAR HOUSING GASKET | 1 | |||||||||||||||||
| 3938157 | FLANGE GASKET | 1 | ||||||||||||||||||
| 22 | 3938162 | OIL PAN GASKET | 1 | |||||||||||||||||
| 23 | 3939258 | COVER PLATE GASKET | 1 | |||||||||||||||||
| 24 | 3939355 | FUEL PUMP GASKET | 1 | |||||||||||||||||
| 25 | 3942915 | FILTER HEAD GASKET | 1 | |||||||||||||||||
| 26 | 4932124 | OIL COOLER CORE GASKET | 1 | |||||||||||||||||
| 27 | 4947667 | REAR COVER GASKET | 1 | |||||||||||||||||
| 28 | 4988280 | HYDRAULIC PUMP GASKET | 1 |
Have fun.
Here’s some pics of the head gasket the leak was behind the head above the trans steady leak , but no noticeable coolant mixing , a little ugly , not sure what made it go , high EGTS? High cylinder pressure ? Only running H1C for now , highest I’ve seen is 1300 climbing up a grade , will bump the timing back a little and hopefully head studs , and the new super 30 will help lower the EGTs to avoid another situation like this …
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Was sort of wondering the same thing since there are 2 bolts right near that leak. Might also check the head for any warp. You mention cutting back the timing. Usually advanced timing doesn't cause higher EGT but it can result in higher cylinder pressure. Having too much fuel and not enough air is usually the root cause of EGT. That H1C is at the heart of that. Although not everyone does it, but an exhaust back pressure gauge is a good one to have in vehicle. You can build one yourself using a second boost gauge or there are dedicated ones available. They tend to be fairly expensive but good info is worth the cost. Those gauges are electronic where the one you build would be mechanical. The one caution there is you'd have a CO source inside the vehicle. If done correctly you'd never have a problem but a CO detector in the cab would be cheap protection.
I never touched the head bolts , I haven’t done anything with the head besides injection pump , timing , fuel pin , gov spring , injectors , so it’s a surprise they would be loose. One thing I did notice is when pulling the bolts the back head bolts were dry and the rest had oil
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I used FP engine kits and head gaskets on my big cam 400 and N-14 and never had a issue...
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