mackrmodel686st

We checked that for corrosion, didn't see any oil. I've seen on the older trucks with the vmac iii engines that the coolant level sensor will push coolant, but not oil.

We tried that already, problem still the same.

I posted over a week ago and got no responses, so I'll try again. 2015 mack pinnacle with the mp7 engine. When the key is turned to the run position nothing happens, when turned to the start position the dash turns on like the key is in the run position. When you let off the key everything turns back off. Thought that maybe the key switch was bad so we replaced it but still have the same problem. Has anyone run into this problem and could someone possibly point me in a direction to start looking. Thanks.

Here's a weird one. Have a 2015 mack pinnacle with the mp7 engine. Turning the key to the run position does nothing, when turned to the start position everything turns on like it's in the on position but won't start. When you let off the key everything turns back off. Replaced the key switch thinking that was the problem, does the same thing. Turning the key to the accessory position does nothing. Has anyone run across this problem? Thanks in advance.

Truck just got a new motor, the old block cracked. Was having the same issue with the old motor. Oil is fine. I'll try the a ground. I'm assuming fuse 40 is for the ecu, correct?

I drive a 2001 cx613 with the E7-427 vmac iii. The truck starts right up in the mornings when cold, but when re starting after it's been warmed up will either have a long crank before restating or no restart at all without starting fluid. The transfer pump has been swapped out a couple times and a check valve was added to the fuel suction line from the tank at the filter housing. No change in the issue. Has anyone had this problem and been able to fix it? Thanks in advance.

That truck had rods and mains done years ago and the jake stopped working immediately after. Oil pressure always seemed on the low side as well but was within tolerance. We were replacing heads and gaskets and decided to try and fix the jakes at the same time.

I would suppose a rag is possible, the pan was off to replace the pump.

The plugs in the rocker shafts are threaded in to the shafts. I've seen what you are talking about, but I think mack did an update to the shafts sometime between 1999 and 2001.

The pump is brand new.

New filters and new pump.

I've got a strange problem with a 2001 vision with the v-mac iii e7-427. The oil pressure drops to under 5 psi at idle if I drive it a few miles. If I shut the truck off and immediately start it back up the oil pressure at idle is about 20 psi. It will stay around 20 psi at idle till I drive it again. Thought maybe the gauge in the dash or the sender was going bad, so we put in a mechanical gauge with a plastic oil line to the filter housing. Both gauges do the same thing. Truck will have about 40 psi going down the road, but drops to under 10 while driving and under 5 at idle. Does anyone have any ideas what is going on? Thanks.

The company I work for just recently bought a replacement engine for one our cx613 mack vision trucks. The new motor is out of a 2002 cu600 mack. Its an E-7 427 v-mac iii. While I was inspecting it I noticed an oil line that come off the oil filter housing and t's off to both jake spacers on the heads. The 2001 truck that we have doesn't have this line on it. Is this mack's fix to make the jakes work with lower oil pressure?

No, hasn't worked in at least 10 years. From what I've been told, it hasn't worked since the rod and main bearings were done years ago. 10 years is as long as I personally know the truck.

It did get a new air to air last year, and the boost hoses look good. I haven't noticed and strange whistles either.