Join Date: Dec 2009
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My truck is an 04 379 Pete, stretched to 315" with a 132" DE sleeper. I picked her up with 450,000 mile on the clock. It ran hot from the start, then just before 500,000 rolled over, the water pump shaft broke, Cat claimed it was a regular maintance item andwould not cover it. Cost $1400 to replace. Less than 3 mths later the Cat Reman pump failed, leaving me needing a tow in Yureka CA. I'll give Cat it's due and they replaced the pump FOC, but I still had to pay for the labor. Changing a pump on a C15 is not an easy job. Next came a new cam, 6 sets of rockers, as the case hardening was lifting of the followers and the cam lobes, along with the pre cooler. The pre cooler is a joke to me. Why mix coolant with air intake? Luckily I did not get coolant into my engine, but the intercooler had about 2 gallons in it. A friend of mine with the same engine had his go and it bent 2 rods. His milage was less than 400,000 and Cat would not warrent it. Replacing the cam, rockers and pre clooer was $6500. Next was the fan clutch, $ 500, then the main one. I started to get white smoke at start up. Was using coolant again, but could find no leaks. Oil was clear. Turned out to be coolant leaking into # 2 clyinder. Replaced the injector and cup seals but to no avail. Whilst warming it up, steam started to come out the crank case breather. Dropped the pan and and it was full of coolant. Removed the head, cracks between the inlet valve seats on #1 thru 5. New head required. Damage done to # 1 & 2 cylinders due to water ingression. Could not replace just the liners, but had to put 2 new kits in. The pistons, and rods were fine, but Cat does not sell just a liner. Whilst reassembling, the threads on the block pulled while final touque on the head. Can't hold Cat responsible for that one, but had to remove head, # 1 liner and heli coil the block. Cat dealer wanted to replace the block, but i put my foot down and had them heli coil it. Total cost for that one was $11600. All with less than 550,000 miles.
I know the truck was used when I bought it, but I did throughly check it out. I'm a diesel mechanic by trade, and short of pulling it all apart everything checked out. According to the download I had done before I bought it, it had no overspeeds but did have one over heat.
Since I've had all this done, the engine has run fine, and has been trouble free. I've kept an eye on the temps, and have not had an over heat. She does tend to run up there though on a good pull in summer, but if it gets to 220 or so i'll drop a gear or so to take the load of it. I feel as if the cooling system is somewhat marginal on the Pete.
I'm not real impressed with the C15. It seams moody. At times it runs quite smoothly, but other times it runs like ****. Shakes and vibrates like hell. Especially around 1300. sounds as if it is mis firing. I put it down to the variable valve timing. Sure would like to find out Cats reasoning and logic behind it. Fuel economy is quite poor. At best I can get 5.2 pulling a box and grossing 80,000 I run at 1200 which is 62mph. Tried lower, but found i need to change down to much. Have gone back to 1300 which gives me the same milage, but also gives me a little more run at a hill. Can leave it in high more. Also found that if I down shift at 1250-1300 and work it up to 1500 it performs a lot better. Letting it drop to 1050-1100 usally means having to drop a gear or more for the same hill. I'm a firm believer in using momentum to get over the rise.