Jump to content

Question for the heavy truck mechanics


Dirt_Floor_Poor
 Share

Recommended Posts

I have a 1994 Freightliner FLD120 that has an N14 in it. Today it started blasting, and I mean blasting, antifreeze out of the radiator overflow tube. I didn’t know what to think, but I figured major engine problems. Just to be sure I unhooked the truck air brake compressor output line and the problem stopped. I then hooked it back up and as soon as the air gauge hits 60 psi, it started doing it again. Is there anything I am overlooking in assuming it is a failed compressor? I called and no one close has it. Looks like the soonest I can probably get it is Tuesday. 

Link to comment
Share on other sites

33 minutes ago, mikem said:

Water cooled air compressor, with a BAD head gasket maybe?

Just a guess.

Good luck

Mike

 

Yes it is a water cooled Holset compressor. Has anyone ever replaced just a gasket and had it hold? I don’t know if I can get those parts or not either. It is the original compressor on the truck. 

Link to comment
Share on other sites

We have a 237 Mack we got in a parts truck in our one dump. It would immediately bubble out of the radiator and swapping the air compressor fixed it.. not sure what exactly you can do to get going again 

Link to comment
Share on other sites

12 minutes ago, bitty said:

We have a 237 Mack we got in a parts truck in our one dump. It would immediately bubble out of the radiator and swapping the air compressor fixed it.. not sure what exactly you can do to get going again 

It doesn’t really matter. I would fix it tomorrow if I could find parts locally, but it’s not a big deal if I can’t. We are close enough to home we are just dumping in the bins with the grain carts. There are calling for rain here tomorrow night and Monday. It has only rained one time, a small amount since we started harvest. 

Link to comment
Share on other sites

31 minutes ago, Dirt_Floor_Poor said:

Yes it is a water cooled Holset compressor. Has anyone ever replaced just a gasket and had it hold? I don’t know if I can get those parts or not either. It is the original compressor on the truck. 

You can get a rebuilt compressor or just a gasket. There are no rod bearings, just a aluminum sized rod. So a lot of times it is shot also so in long run rebuilt compressor is easiest and best. I have seen the coupling spline turn on shaft also so make sure you order spline with compressor. Guys will heat spline to get it off only to have it fail later.

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

here Are pics of the wrench you will need. The single cyl compressor is for the newer engines and double cyl was on the old 855. I have replaced double compressors where one rod has been broken and wedged into side for a while. If you pull just compressor and fuel pump you don’t need to time it. If you pull pulley and accessories drive you need to time gear. A quick way to is turn engine to tdc mark. Pull pulley and mark where key way is. Put key back in same spot reassembling. The mark for tdc should match again also. That timing is just for the valve set though.

C7CFE05B-6DFE-498B-8162-C514C31166F0.png

8107ED09-0099-48E7-9BF3-6078FCA76AD9.png

55224CBE-7972-4825-A875-DF1EE5A36C05.png

Link to comment
Share on other sites

7 minutes ago, MinnesotaFarmall said:

If you change the air compressor, I believe the compressor drive gear is part of the engine timing. You HAVE to put the gear back exactly as it was in the timing. 

That’s only if you pull the accessory drive off, the compressor is bolted on the back of the accessory drive, no timing to worry about

  • Like 1
Link to comment
Share on other sites

I had a bit of luck today as I found out there is a Haldex warehouse close to the Kansas City International Airport today. It is only 25 miles from me. They allow customer pick up, so my dealer called it in and I went and picked it up a few hours later. The compressor was on back order from Cummins, and no one had one. 

  • Like 1
Link to comment
Share on other sites

1 hour ago, Dirt_Floor_Poor said:

I was able to get a hold of the two special Cummins wrenches today. Hopefully they help make this go smooth. 9E5BA144-A124-44AA-A557-F4F0AADE48B2.thumb.jpeg.b3684fc3bb0a50d447da96275566b03c.jpeg

Keep us posted on how that ratchet wrench works.  I have a snap on one and one I made out of a craftsman 5/8 wrench.  They must be few degrees off each other because if you can’t turn the bolt enough to get the next bite the other one will usually get it for you.  Hope your repair goes smoothly.

  • Like 2
Link to comment
Share on other sites

I had my wife run my combine today, so I had a chance to work on this truck.  @Paystar5000, that ratchet wrench worked really good. 


Here’s what it looked like when I started-

A4E4B60D-CED7-4831-8AFD-330604BBA23F.thumb.jpeg.ddb01d5b56d79cde37f3ab5b3ff21644.jpeg


It went pretty smooth getting it torn down with the special tools-

0A02B4B5-F752-4A47-A48A-EB4BABC093E2.thumb.jpeg.01cdcb3024ef45ce005f8472ecded689.jpeg
 

This truck is sitting in a field right now. I got it back together, but it was dark. So no pictures of it completed. I’ll fire it up tomorrow in the light. 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

9 minutes ago, Dirt_Floor_Poor said:

Well the repair of this truck was not a success so far. It is still doing the same thing. We are at a loss for the moment. 

I read your original post more carefully.  I’m not sure if my though here is valid or not but I will share it.  I am thinking maybe there is an air actuated coolant valve some where?   Take off your discharge line from the compressor, cap it  and air the truck up.  That may tell you if it is coming from somewhere else.  I could be way off base here but it seems unlikely the new compressor has a bad head gasket but I would not rule that out either.  

Link to comment
Share on other sites

Yes more than likely a blown gasket or other problem. Inj cups usually put fuel in the radiator just because of pressure difference. I was going to say water pump belt but yours is still in place on the pic. L10 m11 have impeller loosening causing overheat but not big engines they use different setup. Good luck with it. The thermostats are on other side of engine but they either heat or don’t 

Link to comment
Share on other sites

In all years of changing stuff I have never seen a compressor blown gasket. Either no pump , slow pump or broken. Never one like you describe. Not saying it can’t happen because it is discussed on all repair procedures , but I have never seen one. Seen every other part of air system in disaster but not a head gasket on compressor.

Link to comment
Share on other sites

We had pressurized the truck side and the compressor side like @Paystar5000 suggested, but it would only force coolant out when it was running. If no pressure, it would not do it. We finally were able to narrow it down to a problem on the truck side, not the compressor. The heater valve is on a cable, so we could not figure out where air and water could mix. But… the truck has a sleeper. The bunk heater has an air actuated shut off. I turned the knob to cycle the valve and then it quit doing it. I am going to cap it off for now. It seems to be working properly now. I was sure there was no air actuated shut offs on it. 

  • Like 2
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...