How do you make a K run alittle bit cooler? In my baby "Special K" totally rebuilt within the past 1200 hours it has all been done.A nd it still wants to run alittle on the warm to side, compared to an H it actually runs hot. Any Ideas or tricks? I am stumped!
Hope u used deionized water in the radiator......
racers use a product called water wetter, you can find it at summit racing or jegs its supposed to reduce water temps by 30 deg f
Tried changing the thermostat? What does your dealer say?
Does the radiator have copper tubes? The correct amount of rows? Have some of the tubes been soldered off as a repair? Has the rad been rodded out? Are the fins clean as in steamed clean? Do you have the correct fan? A infared heat gun about $80.00 can tell you alot about hot spots and how much the radiator cools from the top to bottom. I've run my K's in 100 plus degree weather without having to stop for cooling. DP
Like DPete said an infra-red heat gun is invaluable for checking/confirming coolant temperatures and is as good or better than the old thermistor probes that were used years ago for coolant temp analysis. There is a spec for the temp differential between top and bottom tank at operating temperature and with the fan at full speed. Your cat dealer should be able to tell you what this should be or they would probably come and fix it for you and charge accordingly if you if you are really stumped Presumably antifreeze glycol content is correct, thermostats are the correct ones and are working properly, everything is plumbed correctly and the transmission is not overheating as well. If an engine overheats immediately following replacement or rebuild, a few things to check are fuel injection and valve timing, whether the fan is on the right way round (yes it does happen) whether you have the correct fuel pump calibration and the correct injectors and turbocharger.
Keep D8K cool. I hate to even suggest it, but have you actually dipped a thermometer in the coolant to see the actual temperature. I've seen more than one Cat have a lot of expensive work done to it just because the temp gauge was faulty. Presume you checked the fan drive pulleys for wear. Cat belts are made to run high on the groove and the pulleys are actually machined with higher sides than normal. If grooves are badly worn however, and belts are riding way down in, the pulleys are worn out and need to be replaced as the belts are likely slipping. Sometimes you will hear a squall and squeal as you accelerate and de-accelerate the engine. Best to replace all three pulleys (drive, fan hub, & adjuster) together with new set of belts. If you shut the engine off, and the fan keeps turning for a bit, they are really worn out. Dpete's concerns on the rad are very valid. If it wasn't taken apart and rodded out, there may be blockage in some tubes, enough to drop cooling capacity 20-30%. Proper coolant temperature regulator is very important. Don't run without one!!!..... Older Cats were built with excess capacity in the form of tubes in rad assembly, but over the years as repairs stack up and tubes are blocked off, that extra disappears. Silica Gel blockage has been a big problem in the tubes, and mostly can only be removed by disassembly and rodding out, followed by a good soaking in the hot tank. External core and fins must be clean, and straight. Sand grid must be clean. Oh yes, is the belly pan empty? If you have by some chance run in the mud and the bottom of the engine is buried in mud, oil and grease plus Twinkies wrappers, this will cause heat buildup as the cast iron can't radiate away the excess. 1" of mud equals 1/8" of steel so far as insulating value is concerned, if I remember right. Deeper matters; if there is a problem with the trans, it may be overpowering the trans oil cooler. Small tubes in this cooler are easily plugged. Same for hydraulic oil cooler if equipped. If brakes are dragging for some reason, or if there is some type of drag in the drivetrain, this can also cause excessive heat that the cooling system can't get rid of. The engine oil cooler is bigger, but bits of rust, silica gel, o-ring and other foreign matter will plug it causing oil temp to go up. Hopefully, no one left a rag in the system causing a blockage. have seen this a few times. Let's see, you mention that the old girl was rebuilt in the last 1200 hours. I'm again presuming all genuine Cat parts were used? These engines ran sorta loose, but if non-OEM parts were used, they may be tighter and not worn in yet. More drag, more heat. Just a thought, suppose all new coolant hoses were used and the pressure valve is new? Older hoses could collapse and cause some restriction. Almost forgot. Caterpillar has had more trouble with water pumps than anybody else I know. Impellers coming loose on shaft mostly due to loose or busted retainer bolt. Sometimes they still turn but actually slip on the shaft slowing down coolant flow. On to the fuel system; Was it rebuilt and properly set? Too much fuel, lots of extra heat. Lots of black smoke, very slow windup, may be a bad turbo and again, lots of heat. Gad! There are a zillion things that will make an 8 run hot. I just can't remember them all, but hope these help. Good Luck!
I read on one of the Cat boards that someone cured theirs running hot by rerouting the thermocouple sensor wire as it had been tied off too near something hot like the manifold.I know this is a wild shot but if it proves to running in the normal range and the gauge reads otherwise it might be worth a peek.Had it not been disassembled for rebuild I would not have considered this.Ron G
D8K running warm. Hi, RonG. Surfer-Joe covered all the things I would have suggested and somebody beat him to having the radiator serviced, including rodding out, if it hasn't already been done. And maybe even it has already been 'done'. It wouldn't be the first time that a repair shop has charged for work they haven't done. Trouble is you can't get a good look at the tubes without dis-assembling the radiator. Wulf mentioned some valid points to check too, as did several others. Personally, I think I'd start with another temp guage and check that it IS actually running warm. If it is running warm, I'd look next at the thermostat and check that it is opening at the right temp - or far enough - or at all. After that, work your way through all the 'possibles', starting with the simplest/cheapest and working your way through them until it no longer runs warm. The D8K's, like the H's, were very reliable in the cooling department with BIG mobs of excess capacity built in to the system. Your thought about the sensor wire is not silly either. Hope you fix it cheaply.
Just a shot in the dark but I have seen a lot of over heating problems caused by silicone sealers. During rebuilding a lot and I mean a lot of people think if a little is good then more is better. But this is not true to much of the magic sealer and it comes loose on the inside of the engine and blocks water passages,oil screens etc. Oil coolers and radiators are real good filters for catching this extra sealer thus an over heated engine.
Did in a big overhead Cam Box on a 2000 Hp MTU once...cause of failure...restricted oil galleries to the bronze rocker bushes.....clogged with silicone.
Good point wrenchbender, silicone is a bad thing to use as a gasket maker especially in excess. DP
CatSkinner77V, There is one other thing that hit me today while I was working on an old cat scraper. If you have a big enough exhaust leak it'll blow hot exhaust through the radiator causing an over heating problem. Well it don't really have to be real big if it's pointed in the right direction.
Now where would you ever find a Cat scraper with a big exhaust leak?..........
Only in the southeast :falldownlaugh
thanks for all the suggestions fellas, I just pulled her into the shop tonite. I think the rad is internally clogged. It was a used rad, fins are in very good shape, it come off an old scraper cat so it was never in the bush really. But I don't think it was ever rodded out, atleast not in the 18 years we have had it. I rebuilt the engine myself, and used all cat parts, I don't think the problem lays within the engine itself. I think after i get this cooling problem dealt with, I am still gonna find some of this "water wetter" stuff i have heard so much about. I do love my fancy fluids :drinkup haha. I run Lucas oil stabilizer in everything, it really helps in older engines, slows the blow by down quite alot and reduces friction on dry starts. Its just that i have heard horror stories about K's running warm all the time, because they cranked up the 342 another 30 horse compared to the 46A's. And it imposed alittle more heat on the system.
If your rad is off of a scraper it may not be the correct core for a D8. If it is an oem core there should be a tag on the fins with the part #. DP
Catskinner77V, My D9G was running warmer this last summer. Ended up buying a new radiator core from these guys: Rocore Industries Inc. Franklin, Wi Phone 800-621-6067 Ordered it thursday, april 19. They made it on the 20th and shipped it. Got it the next wendesday the 25th. core price 2000, went with steel fins spaced a little bit farther apart. shipping 250 wisconsin to kansas, was packed in a wood crate Kent
its not off a scraper, an old scraper cat, as in a D8K that always pulled a scraper and never had a blade on it.
My mistake, I got scraper cat mixed with cat scraper ointhead DP
Like others say, check the temp for sure with a good thermometer. I have had exhaust leaks heating up the tube that runs to the gauge cause erronious readings on the temp gauge. So like was mentioned routing it is very important.
Please ,Anyone knows where the thermostat is located in cat D8k 1985/ 66v ?