Mack Technician

Service bulletin SB273009 coolant level anti-capillary jumper harness.

Be aware RED! Don’t wreck your new ECM.

What Fred is talking about is capillary bleeding through the wire. The sensor in your coolant tank ruptures internally and 10 PSI will push coolant down the wire using it as a capillary tube. That’s how coolant gets in past the seals of the J connection.

Its not likely coming from outside in, but rather inside out. You can pour coolant over the outside of your ECM all day and the seals will keep it out. The capillary failure is coming straight in via the unsealed wire. Coolant flows down the wire like a pipe.

Mack makes a jumper you install in the wire connection leaving the sensor. It’s a few inches long. The jumper has a sealing compound pressed into the wire strands. If the coolant sensor ruptures the coolant will hit the protective jumper and dead-head. 

Mack was handing out jumpers back in the day. Check to see if you have the jumper. If you don’t, install a new coolant sensor and jumper. If you do, install a new coolant sensor and jumper anyway..... cheap insurance. 

3 hours ago, R.E.D said:

 

What's the best way to clean up these connectors and pins?

 

Thanks 

Red

That's ugly......R.I.P. ECM

For future......I was given a small 5 Oz can of Deoxit D5 by Liehberr. Stuff has been my go to. Hit it with regular No Flash electrical cleaner then Deoxit and reassemble.

The machines Liehberr sold have to rotate continuous, so they are running sensitive Serial/CAN lines through a constant rotation brush style electrical connector. That Deoxit is the only stuff that would lubricate/clean/maintain a connection. Regular Dielectric grease lifted the connection stinger off the contact disc and set codes.  

Get your Coolant Level Sensor Capillary Jumper in there ASAP. I thought all trucks got a free one from Mack? Maybe someone failed to follow up? Your coolant sensor harness wire is also filled with coolant.

This is what your about to buy.... It's just a helluvalotta tubing and jargon.

This is what you would like...….

Hard to work on, but not a bad engine overall. It has the complications you see with the introduction of tier 3. A 2002 would be a better engine.

K&S sells Bosch reman @ $300.

Google “Mack E media”. They sell complete wiring diagrams. $22.00 

Welcome to BMT. What chassis is the E-Tech in? What make/model?

If you have no air moving at start up it is not a freeze issue. And you say the fan completely stopped working suddenly....

You need to stop and get your HVAC (heating, ventilation, Air Conditioning) dash blower working. If blower motor fails to work on all three speed levels then check to see if you have a blown fuse. If fuse is blown (or circuit breaker fuse failed) then replace it and retry.  

What are you looking for(or at?) under the hood when the A/C stops working?

Quote

I pulled no over let the hood up turn the controls on I get nothing out the vents not even hot air.

Blower motor in dash. It works properly and always moves air?

Failed water valve can still leak hot water when fully stroked to off position. Do as Cmac suggested and clamp the hose.

You have no working HVAC fan?

I like the heater water control idea more that the stinger, they were notorious for leaking hot flow, but it can't explain zero air flow and then HVAC system working fine next time you run it? Freeze up would cut your air off completely and stop the air flow.  

Doesn’t look like you ever accidentally backed over it in the woods during 38 years? Good job! 

On 7/16/2019 at 9:18 AM, Mack Technician said:

Be ironic if this thread became the explanation to Billy’s lack of interest?

~Blabberer esq.

Be ironic if this thread became the explanation to Rob’s lack of interest?

~Blabberer esq.

8 hours ago, JoeH said:

Why did you dig up a 9 year old thread to tell us your email?

You’ll never hear the answer to your question Joe. BMT can be a dark and mysterious place. 

Pull air cleaner and inward mount bracket. 

Time to come over to the dark-side   and drive a truck that makes Prius drivers swear out loud?

The payback is that you won't have to shift that T300 Mack transmission so much. AMI-370 is a good program and candidate.

You failed to properly insert the freeze stinger into the dash evaporator core. It’s too shallow. Your symptom perfectly describes “freeze up”. 

Get a clothes hanger, straighten it, Jam it into the core where the freeze stinger is planted, once it’s hogged out put the stinger in as deep as you can. 

WHAT!!! $100.00??? Hosed! Give me your part number and I’ll try to find a cheaper source. 

On 8/10/2019 at 8:57 AM, Deere Mack said:

Thanks for the all the tips!  I haven't got back around to this problem just yet, other problems got put in front of this problem.  Think I bought someone else's problem or my ocd is getting the best of me.  I like everything to be right!

Your OCD getting rubbed raw on that AI engine? Or liking it?

On ‎8‎/‎17‎/‎2019 at 12:43 PM, Vision 618 said:

So,  I changed 2 and 6. No problems! Yesterday,  an 8-6 code started intermittently popping up.  Before it was an 8-2, that's why I changed number 2 to see if that code would go away.  Figured if it didn't, I had a wiring issue.  I never got a 8-6 but I changed it because there was fuel leaking around that one.  No change in engine performance when the code pops up.  20 year old wiring harness perhaps?

So the 8-6 continues to pop even after changing the EUP?

How much are you paying for your EUP's?