Hi all, I was hoping to get some advice.... My air compressor is leaking from the mounting gasket so I am going to pull it and replace the gasket. I assume I can't just pull it and replace the gasket and bolt it back on. Maybe I can. Figured I would ask. I will give as much Info as possiable. Ihave the 6C8.3 cummin motor (300HP) in a 1998 pete 10 wheeler. The part number for the compressor is CP9149-05 the gasket I'm replacing is 3913287. Any input would really help. I just had to get new walking beam bushings and springs for a little over 4k so I have to do this myself the shop is not an option. I would also be interested in a shop manual for my motor if any one has any info on where to get one. Thanks all!!!! I could not function without the advice I get from this forum.
Not familiar with your motor, but any I have changed, it's pretty cut and dry. If you're lucky you might be able to do it without removing the coolant lines. Never heard of a compressor that was timed. Pull it off, clean it , and re install. Just make sure no to force what ever type coupler it has. I think Cummins just has a gear mesh. I'm sure someone knows for sure will chime in. Any experience I have is with stuff from the 70s and 80s
Is the compressor leaking oil from the point where it attaches to the front crank cover? Are you leaking antifreeze from the head? Oil from the head? Do you have a power steering pump that mounts behind the air compressor? I've had issues with a 8.3 leaking oil from the crankcase cover mounting bolts. Mine had simply gotten loose from the case. Be aware that the rear crankcase cover is aluminum, and if the compressor gets loose it can bounce around and crack the cover. You need to look the cover over closely when you have the compressor off and make sure the cover isn't cracked. If it is, its a job, because everything on the front of the engine has to come off to replace the rear cover. Hopefully that isn't the situation for you. Red is the front cover attachment point- Yellow is the head area- Blue is the power steering pump- which yours may not have in this location. Where are you leaking and what's leaking? Air, antifreeze/ water, or oil?
Like Crane Operator said, I've seen them crack the aluminum cover at that point. Clean well with brake cleaner to check for cracks, keep the bolts tight, make sure there's a brace like the one just in front of the blue arrow.
For a manual- I always just get one off ebay- I prefer a paper manual over a cd rom. Just type in 8.3 cummins manual and you'll get a assortment. https://www.ebay.com/itm/323433243815?hash=item4b4e1fa4a7:g:xikAAOSwMudbkZmY
actually some of the cummins have the compressor timed to the engine. It’s not a huge deal if they get off time. They were timed to prevent a slight vibration. I had to do it on a 6.7 in a barko harvester.
T hat's a far different engine than the old 290s sitting slanted in a Ford Louisville.
What about the old ones with the fuel pump behind the compressor. I had always assumed that with push rod injectors, the fuel pump wouldn't be timed, but now I'm not sure.
Yeah- they are more similar to a cummins 5.9 than a 855, as far as fuel delivery and accessory drive.
Which air compressor do you have a Holset or a Bendix ? Bob
no antifreeze leaking and yes where it mounts to crank case is leaking oil. it looks like the prior owner put some calk around it to stop the leak. I will be sure to first check the mounting bolts for tightness. as for air I am leaking a small amount I can still pass a bleed down test but left not running its 100% drained in a few hours. my power steering pump is in a slightly different location. I need about an hour and will post some pictures. THANK YOU FOR YOUR HELP!!!!
I will do!!! there is a brace but it is missing a bolt and the other was hand tight at best. I did notice that the other day!! THANK YOU
here are some pictures..... it looks like I may need to replace the the second gasket back too. I will include this diagram from cummin. I'm thinkiong part number 61 and 49
I doubt that gasket 49 is leaking but with the compressor out its not a lot of work to replace it if just for peace of mind. Properly torquing the bolts in the support bracket at the rear of the compressor is very important. Clean the bolt holes with brake-kleen or a fast drying solvent and Locktite them. The reason the gasket failed is because the support bracket came loose.
Thats a Holset compressor . You will also need the gasket where #26 is but the one to mount a pump. You will also need 4 blue olive seals for the water lines. you may be able to move the steering pump back enough to get the compressor out. While you have the compressor out carefully check the housing between the gaskets for a crack. Bob
If the front accessory drive plate is leaking also between it and block, it's cam out. Done 11 of those.
ok well i will match up the bolt to get another as one is missing. I can find tourqe specs on cummin site im sure. ill add brake kleen and locktite to my list.
#26 is listed as hydraulic pump gasket. is that what your talking about? forgive my ignorance but blue olive seals? what should i google to find them? thank you for your input!!!!!
I’ll second this mike l, when I worked at the Cummins tech center the single overhead cam ISX had just went through development and the air compressor was timed to the front gear train to reduce noise to be compliant with certain db level standards.
I always time the compressor on a 855, but from one Cummins manual to the next version it's conflicting. One Cummins manual will say to time the compressor the next it's not needed.
I think engineers have trouble agreeing with one another at times.
The 26 gasket is the steering pump mount gasket, and the blue seals are the water pipe seals a grommet type seal. Bob
i saw a video on youtube on how to hold the time but that was on the ISX. I have the 6C8.3. thats why I asked if this one was also timed.
ok I found them!!! but do you happen to know the size 1/4"? I would just like to get everytrhing needed then pull it so I can complete the job in a day so I'm not down for days waiting on parts. I just ordered #26 and #49 from my local cummins supplier. I'm going to get brake kleen, locktite and for the support mounting bracket a set of the M10 bolts with lock washers.
Maybe I should not comment as it's been maybe a decade or two since I actually worked on an 855! but at least some of the ones I recall the most important thing about timing the compressor was to have the "tune-up" markings on the front pulley line up with marker for setting the valves and injectors. Might be giving my age away but recall some where the crankshaft for the compressor was one piece with the shaft coming out the front of engine for that accessory drive pulley! Seem to recall that back then you could buy a rebuilt compressor without a crankshaft. Just the connecting rod hanging down from piston and you had to work the rod over the end of the crank to remove and then install the compressor.
I just want to say THANK YOU!!!! to everyone from this community!!! I would not be as far as I am in my business with all of you guys!!! Out of curiosity dose anyone Know the amount of engine oil for the 6C8.3? there seems to be a discrepancy... on the cummins site it gives a ton of options.... I will include picture. then i have another pic I will include from original operation an maintenance manual. I ask because I drained out 5 gal with filter change. I read the manual as I need 6.3 gal with filter. I put the 6.3 in and the dipstick was way over. I drained 1.5 gal back out and now dip is reading correct. just not sure what to do.
The amount is, fill until dipstick says full. Unless the dipstick is wrong.
If any cummins have a TwoFlo compressor instead of a single cylinder {SS296}, the twin does not need to be timed. IIRC.
The varying oil capacity is because there's all kinds of different oil pans available. I think around 5 gallons is what mine take.
Like I said above it's be a long time since I worked on a Cummins but thought there was a section in service manual or operators manual that listed the capacity of the pan by the part number of the pan.
ok I'm sorry guys one more question that has me nervous..... I will first say my coolant temp gauge is broken and is going in shop to get fixed on 5/16. Ive tried to fix it. with that said.... I did a coolant flush. there is coolant filter shut off valve if Im reading it right the whole time i have had truck it has been shut off. i will post what manual says. my question is what position should it be in? the next post will have the position i found it in first so the whole time I have had truck followed by how i think it should be according to manual.
first how it has been second how i think it should be. anybody know for sure?
I would say it should be how the second picture shows for flow, and if your still doubting, there's a easy way to tell. Pull the filter off with the valve how it is in the first picture- there should be no coolant running out of the engine. With the filter off- turn the valve the way the second picture shows, and coolant should run out of the engine. All the valve is for- is so that you can change the filter without all the coolant running out of the engine while you have the filter off- i.e. so that you don't have to drain all the coolant just to change the filter.
ok thank you!!! it just made me nervous because it says failure to turn flow back on can result is serious engine damage. I will say when I was draining all coolant out when the valuve was like it is in the second picture it drained better. anyways I will try i was just hoping for another option because i got the filter per loaded with the DCA so I'm afraid if i take it back off additive will flow out. Thank you for your help!!!
with extended life coolant there is no need in a filter, engine manufacturers have stopped installing them. If that filter has the additive pellet it will over charge the system. So all you need is a standard filter that has no pellet. You can leave it turned off.
I made sure to get heavy duty coolant, nitrate free with no additive in it. its made for class 7 an 8 trucks. I'm assuming my level is about 1.7 per but i have a test kit on the way.
I'm sure you mean nitrite-free not nitrate-free coolant. Got a photo of the container, espcially the part of the label where it mentions to what ASTM Standard it conforms....? Coolant filters are/were from a bygone age of "anti-freeze" rather than coolant. Older types of antifreeze required the coolant filter (in truth not a filter at all but a canister full of SCA/Supplemental Coolant Additive) - that's why it rattles when it's new) that slowly dissolves as the coolant flows through it so as to maintain the SCA at an acceptable level . As TS pointed out above, the latest generation of Extended Life Coolants do NOT require SCA. In fact the presence of SCA in an ELC-type coolant will actually negatively affect the ELC. So it's probably a good thing that the valve on your coolant filter was turned off. Also you cannot test an ELC-type coolant with an SCA test kit.
i found this coolant on the fleetgaurd cross reference chart
You've opened a can of worms now. I thought they all had filters in them. That one contains 12 units of DCA4, so it is not intended to be used with that OAT ELC coolant. You can get a "blank", that is filter only, filter without the additive. Probably not needed with ELC, the old coolants you'd add some SCA "just to be sure" even if you didn't have a test handy, then they would drop out particles that the filter was supposed to catch, to avoid wearing out the coolant system with circulating abrasives. If you haven't run it with that filter, take it off and get a filter only. Maybe still take it off even if you've run it?
Cat dropped coolant filters 25 years back, Cummins had them up to 2014. Cans of worms, cans of worms.
Yup, that’s an ELC. Don’t need the SCA with that coolant. As above, get an empty canister and fire it on there in place of the WF2074.
so the coolant I added is considered a (oat) coolant? got it. replace filter with a empty or non dca loaded one
It is. It says so right there on the label and also it conforms to the correct ASTM specs to be an OAT coolant, more commonly referred to as an Extended Life coolant or ELC. I see from the container it is a concentrate not a premix. I hope you mixed it with distilled or de-ionized water and not tap water.
Like Nige said its on the label:
Made by Quaker Oats. Oats make a great radiator stop leak too.
I installed some coolant filters on an old fleet years ago with kits that were available. Always used the non-additive ones. They caught a lot of the junk from poor maintenance. So if this truck is old and neglected, good to use some fresh filters on it from time to time. Also keeps them from rusting solid to the filter header, not like an oil filter where you can get away with it for a while.
yah i got distilled water from the baby aisle at Walmart. so my problem is i did run it for 10min right after i refilled it. i fear the additive has already mixed with the coolant so a empty filter would be a moot point. should I drain and refill it?
Probably OK, it didn't run long enough to fully dissolve the pellet additive.
i got a wix 24070 no additive.
can I just run it with the filter valve turned in the off position? just for a day until the new filter arrives?
yah got a new empty filter on the way!!!
THANK YOU ALL!!!!!!! I guess the problem is resolved now. new filter here tomorow!!!! I will update everyone when I remove compressor next weekend on how adding the new gaskets goes. I did notice the "missing" bolt on the support bracket is not missing just snapped off. so I will have to extract it to put a new bolt in but that should be easy enough!!!
Pretty common.
anyone have a recommendation for power steering fluid? I see its listed as ATF type E or F or dextron II. Can I use a full synthetic dextronIIII?
why would you want to? Bob
read on another thread that some one perrferd to use that for there cummimngs. so just get basic atf?
I wouldn't buy synthetic for power steering. Seems a waste of $$$. Plain old ATF is all I do.
thank you I appreciate you!!!!