I think I am a patient person. I also try and do things logically spending only money when it needs to be spent. So, when I got the truck on the road last June and it was running above 210°. I decided to do the next step up cooling system modification. I installed the Heath Diesel 21" plastic cooling fan and heavy duty fan clutch. I had a new Delco HO pump on the engine, but a several hundred thousand mile 1998 used fan clutch. It made sense replacing a well used and not functioning correct part.
I wrote about it at the time in this thread. It was much better, but I still couldn't run 70 mph with a load in high temps while pumping any kind of boost out of the turbo. Further researched showed I hadn't researched enough in the beginning. The HO pump casting doesn't mean it is the high output pump. It is just a casting mark for the foundry that made the housing. I could replace my HO pump with a real high output pump. Or, take the next step and get a 1999-2000 high output pump with a bigger front bearing, screw on fan clutch and bigger impeller.
Getting the screw on fan clutch water pump means a Kodiak Severe Duty fan clutch will fit. This is the same fan clutch the Duramax trucks used too. Of course, these bigger and better parts aren't cheap. It isn't just a step up, it is a walk up the staircase. Both in price and performance.
I lived with things as they were while it was cool out and saved up the cash. Now that it is getting warm again, I got everything ready. Monday, I brought the truck into my class and pulled the fan clutch, water pump, balancer pulley, balancer and front main seal. I was pretty shocked to find the coolant with was new 50/50 mixed stuff last spring came out a nasty rust color. I hadn't pulled the radiator cap in a few months. I figured out last summer my overflow tank works like it is supposed to so I just have been giving it a glance. Only nice green stuff in it.
Not oily coolant, rusty/dirty coolant. The radiator was rodded out last spring. All new hoses and new heater core. The only thing that wasn't new or cleaned out chemically was the block. I think it must have rusted some inside sitting for years since it was pulled from whatever HMMWV the military had it in. I can see that effecting cooling a little, but nothing is clogged and there weren't any chunks or clumps coming out. I will just refill with distilled water and do the garden hose flush once I get it on the road again. Maybe do the HE laundry detergent clean trick and thinking real serious about a coolant filter too.
We got it all back together again yesterday afternoon right at dismissal time. I fired it up, was really pleased to feel a breeze at my hands when holding them in front of the grill guard. Lots of air was moving! Then I saw a river of oil running onto the ground under the truck.
I shut it down, got rid of my students and went home without even looking for where it was coming from. I started looking this morning. Water pump and balancer areas were still pristine. I fired it up and saw oil getting pumped out of the mechanical lift pump vent hole. Not fuel, oil. Yeah, I love changing diesel lift pumps.
I checked the engine oil and it was the same basic level as before so I think it was just putting out oil, not fuel into the oil. I have several used ones, but since it looks like pulling the Banks cross over pipe is going to be the only way to get to it. I am only going to put a new Delco unit in there. I have one coming that should be here next week. Which is our spring break so I might have it back together again in two weeks.
The past two weekends I have driven almost 300 miles each in the Cowdog pulling a M101A2. I noticed my oil drip pattern had changed to not just under the front main seal to pretty much the entire front axle and passenger side frame rail. Not a bunch, but it was more. That is why I finally broke down and got the parts swapped out. Now I am starting to wonder how much the front main seal was leaking and how much was fuel pump all along?
The fuel pump on the truck will be the 3rd from last thing I have on the truck that wasn't replaced new when I redid things. Only the power steering pump and steering box are left. They are both seeping and are planned to get upgraded as money allows.
The moral here is if it rubber, has seals or is over 20 years old. Replace it while you have easy access. Like on an engine stand in a climate controlled room. Otherwise you will end up hugging a dripping oil and fuel front axle having to do it. Did I mention I can't wait to change out the lift pump?