JoeH

Describe the hard starting. If it has a bad head gasket and coolant leaked into the cylinder you can break a crankshaft trying to start it. Water doesn't compress. My dad broke one that way on our Case wheel loader years ago. If a piston is waterlogged it'll struggle to get passed compression stroke on that one cylinder, even if batteries are good.

Not sure, but don't run it with antifreeze in the oil! Youll destroy the bearings in the engine. Not sure what the V8s used for an oil cooler, I'd suspect that or a head gasket. Do a compression check and see if you have a cylinder with low compression.

Can you get one with a manual transmission? I know shifting linkage would be crazy with a tilt forward cab, but it could be an interesting setup for future needs. Truck would get off road on occasion, thus the desire for a manual trans. Need to be able to power through soft grass without bogging down.

Those look really nice. I might be convinced to get a couple sets, one in that dark grey and another in tan to match my 79 R if it lasts long enough to restore. The tan one I might like a whole interior for, would be best to do it all in one shot so everything matches. I don't see holes for the window crank and door handles. Are those mark and drill yourself? I know a local guy that does interiors for classic cars, if he were interested I might be able to get him to make and sell interiors for R cabs. The price would have to be right and there would need to be a demand. He would need samples to work from.

How are you making out with the truck? Get any sensors sorted out yet?

H&K put the new rails in, not us! Rails are probably 5 years old! They traded 60 old trucks in as part of a deal with Coopersburg Kenworth for new trucks. This is one of the better trucks they traded in.

Interesting, never noticed. I think they did modify the cab a little here and there, I think the roof on my 95 RD is a little different from my 1979, but I don't recall for sure.

We just retired the 1980 DM686sx, the rear of the frame is cracked horizontally about 8 feet from rust. Refurbishing the mixer to go on a 1988 RD690S with new frame rails; used to be an H&K truck.

It's a great engine hoist, but we only run older Mack's, soooo... We never use it for that. 😎

One of our yard trucks, not the original frame, this frame came out of a garbage truck that caught fire. 237 horse, 5 speed maxitorque. Steel dash. Never goes on the road. Head gaskets been blown for years, but it fires right up and helps out around the yard a few times a year. No rust holes on the roof! Second picture replacing roof, first picture picking parts off a concrete mixer.

For those of us who have never heard of them, what's a plus 3 cab?

Still in Huntingdon valley?

Another local boy! We deliver to holicong on occasion! Bucks county is a nice area. Rob, I like the old style R hood on tandem axle trucks but prefer the new style hood on triaxles. Most of all, I love how the old maxidynes pull. The endt676 in that '79 is very well suited to that truck at a max 52,000 lbs. We just picked up a 1988 em6-300l, won't know for a few months how it compares to the endt676 because we're renovating a mixer to go on it.

😛 nice to see someone local whos seen our trucks! The collision center is one of our numerous tenants, we own and rent out the 7 acres it's on.

Welcome to bmt!

Goes out nearly every day during the concrete season. Had roughly 350k miles when my dad bought it in 1986, we have put another 200k trolling around in our 15 mile delivery radius. Last thing the engine needed was a piston and cylinder head when it dropped a valve seat 8 or 9 years ago. How's that for up time?

Rears are 44k, that's what S indicates in rd690s. St would be 38k rears, sx would be 55k rears. According to the below website, the 90 in 690 indicates a maxidyne engine? But I didn't know they still made maxidynes in 1999. Maxidynes we're usually 300hp I think. Someone more knowledgeable will probably chime in. The 6 in rd690s indicates a standard highway frame. Should be a double frame, that's what my 95 rd688s has. Watch out for rust separating and cracking the frame flanges, that's a $25,000 dealer replacement job. https://onlineuniversity.bloomfire.com/posts/2387484-mack-trucks-vin-decoder

Rofl. That van owner cracked me up. Just get off the street...

Lol. Some of the rammyest drivers I've encountered on the road have been Swift trucks.

Give a call.

Rob and 1965 are right, check fluid levels and ground connections. If you're low on fluids they'll overheat, giving you a code. Make sure battery cables are clean of any corrosion and are tight. Check air filter, make sure is clean and not restricting air flow. I had just got off a 12 hour overnight plowing snow, so I wasn't typing straight. Could be bad sensors, but also could be that sensors are trying to tell you there's problems. Regardless, you're a far cry from needing an engine rebuild.

Hopefully the problem is the sensors and not the wiring harness going bad. Vmac III book tells how to test the circuits to determine where the problem is, wiring or sensor. Sensors are easy to replace, that's where I'd start.

Don't need to. They'll become inactive faults, and the light will go off. Light only comes on for Active faults. Sensors tweak the voltage on the circuit, which the computer uses to determine what's going on. It throws a fault code when the voltage in a circuit goes outside the programmed voltage range. When voltage comes back into the proper range, the active fault is no longer present, so the light will turn off. Assuming there's no other active faults.

Go to your Mack dealer and order V-MAC III Service Manual #8-211 and ETECH Engine Service Manual #5-106 8-211 has all the blink codes, the procedure to get codes, and how to diagnose the code fault. 5-106 has all the mechanical information on the engine, including sensor locations. Great intro section in it to give you how the computer runs everything. If it were my truck, I'd use the books to go through and change all those sensors. 4-2 is possibly a faulty Fan Clutch Solenoid. You should have some fun with knocking out those codes, I'll bet that faulty exhaust temp sensor and the ambient air sensor is your boost problem. Failing sensors are telling the computer the EGT are hotter than they really are, and so the computer is cutting back on the throttle.