Jizzo17

I wasn’t necessarily looking to cheap out. I just didn’t know if there were any other options available.

Got a call back from the radiator shop today and the tubes were clogged to where it was only performing at around 25% cooling capacity. They flushed it out but the scale was so severe there were several holes that appeared. When one was fixed two more would pop up. I was quoted 2300 for a new radiator core but I was hoping someone on here might have another avenue for me to look into.

Okay thanks will do. do you advise taking the entire oil cooler off before I blow air into it?

I just took the forward facing end cap off. It’s the one that bolts to the water pump. The system will pressurize because it will blow the cap off the radiator if you remove it when it’s hot. i don’t have new gaskets but I can cut some out or get my Mack dealer to order some. I bought this truck from a lumber yard with 560k+ miles. I added the plus because the odometer stopped working at some point and there’s no telling when that happened. So I’ve become increasingly familiar with this truck the longer I’ve owned and operated it. But this is my first time with this type of oil cooler.

Here is a picture of the oil cooler tubes. I ran a wire through several of the holes and there is some sludge inside. Could I just blow air through them or can they be replaced?

Thanks. I thought so. Would it be possible for it to be plugged as well?

What is the round tube that the water pump forces water into? It’s in front of the 3 oil filters on the driver side of the engine.

I was afraid it might be the radiator. The old pump has a date stamped ‘86 on it but was not pitted and turned fairly easy when separated from the fan clutch. The fan clutch itself still had resistance. I have the radiator detached to the point where I was able to lean it forwards and pull the pump and fan out as one unit. So a few more hoses to unhook and I can lift the Rad out. Being as the pump was original I would bet the radiator is also original to this truck lol i am getting coolant flowing throughout the cooling system. Would plugged tubes still allow that?

How would I check for this? I may end up ordering a new water pump and slapping it on regardless. Would a new fan clutch be recommended as well?

I’m having a coolant issue on my 1985 Mack r with a em6-300. VIN is 1M1N179YXFA099577. I have flushed the coolant system at least 8 times with cascade powder. It was finally running out clear when I drained it so I put my new thermostat in, new water filter, and filled the radiator with the red coolant and distilled water at around a 55/45 ratio. It was holding temp at 180* with a few test runs I made but I was hauling gravel today and it got up to 230+. I wasn’t concerned at first thinking it might be a faulty gauge or sensor, but it started puking water out of the radiator cap. I parked it and let it idle but it still never came back down below 220. The fan feels like it’s pulling a good amount of air through the radiator. So I’m led to believe it may be the water pump. Has anyone else had any similar issues? thanks.

Okay thanks guys. Do I need to pull both seats out to get that floor pan off?

It is just a straight 5 speed. It won’t do it all the time. There is just a range of engine rpm and travel speed that it wants to pop out. Which is very close to the rev match to float into and out of gear.

I was hauling gravel yesterday in my 85 r model and under load 4th gear kept popping out when accelerating. I could apply just a few pounds of pressure to the gear shift lever towards me and it would stay in like normal but if I held it forward it would keep trying to kick out. Is there an adjustment that can be made to the linkage that will fix this or am I going to lose 4th soon?

I found a 90 that I need but it came out of a 75 Mack with a 5 speed. And the owner says it’s more like a .85 to one ratio. Does this sound like it could work for my truck?

@mechohaulic the ratio is 1:1. Tag may be there somewhere but just scraping the dirt off with a pick I couldn’t find it. There also wasn’t a washer in there when I pulled it apart. The only thing that came out were the two broken pieces in the picture.