Hi Y'all, im looking at buying a D7H from a cat dealer and when i went and looked at it i found oil in the radiator. They then replaced the engine oil cooler and water pump flushed the radiator 3 times and worked the machine for an hour. The machenic said it still has signs of oil in it and is still putting a few bubbles in the radiator. Ive spoken to 2 Cat mechenics who say that if it was an internal problem ie head or liners dropped it should also be putting a certain amount of water in the oil which as far as i could see it isnt, oil was black not milky at all. Would be greatfull for any input as they dont seem to want to go any further and have offered me a price as is, if im up for a full rebuild straight up i have to factor in another 25k. Thanks in advance Hardcountry
Oil in the rad is easy to fix, Flush with water and liquid cascade (dish washer detergent) a few times. Its the combustion in the rad that isn't easy to fix. Have it checked for combustion gasses, We use the blue dye that turns yellow in the present of combustion gasses. if they are present then there is pretty involved fix. We just rebuilt a d8k that had a dropped liner. It put combustion gasses and oil in the rad but only a little water in the oil. not enough to see but it did show on the oil sample.
Did they pressure test the cooler that they removed to prove it really needed to be changed or do you get the impression they were just changing parts for the sake of it, hoping that something they changed would cure the problem ..? When they "flushed" the radiator did they use dishwasher soap or something similar and non-frothy to get the last traces of oil out of the core and coolant passages ..? If they didn't use some sort of soap then it would IMO be almost impossible to get all the oil out with just a water flush. A cooler failure (or a head gasket/liner seal failure for that matter) can put a small amount of coolant into the oil if the engine is shut down while it's fully up to temperature. The pressure in the cooling system (and no pressure in the oil system 'cos the engine's not running) will force the coolant though any crack in the cooler and it'll find its way into the sump. Did the dealer pull an oil sample and check for the presence of water and/or glycol in the engine oil or are you just relying on a visual inspection of the dipstick ..? Generally oil in the radiator will likely be a cooler core failure, but they already replaced that. It sounds to me as though they didn't do much of a job cleaning out the cooling system TBH. Wouldn't want to bet too much money on it though.
d7h should have a cooling system pressure gauge,run it for 30 min or so under load if pressure goes into red you have big problems,if it stayes in yellow should be ok.3306s would show some bubles with no rad cap on or releaf valve broken. but the dy in water preveous poster is a verry good idea.
Thanks for the input guys, they did test the old cooler and said it was fine, why they didnt test it before replacing it is beyond me, they did the same thing with the water pump, but after dealing with these people for the past 3 weeks nothing should suprise me. I think if i buy it and get it home ill take your advice and put the dye in the rad and get some oil samples done before i start pulling anything apart.
In that case I think I would walk away from it unless the price was really cheap. Just a trace of coolant in the oil will make the oil get very thick as the oil neutralizes the antifreeze.
Run it for period and let set over night then crack the oil drain and collect a small sample in a clear container if water present you will see it
I think if it was me I would be having them do the oil samples and the dye in the radiator BEFORE I parted with my money ......... Effectively what you saying is that they have changed an oil cooler and a water pump, both of which were later tested and found to be OK. Therefore as I see it the problem should still be there, or am I missing something..? Do what a mate of mine would do - the conversation would go something like ........ "It's fcuked, I'll give you $500 for it" ........... The worst effect of glycol in the oil is that it will strip the lead-tin overlay from the crankshaft bearing shells and could later lead to a major crankshaft failure.
I feel like I'm missing something here. I thought the whole purpose of dealer repairs was the guarantee. Get clear on who pays for what. Take it home and do ALL of the tests and cleaning mentioned above. Work it hard, test it again, and if it fails the dealer should fix it. The other side of this is that if they cut corners and didn't finish the job then what else did they skip over?
sounds like a crappy dealer to me. maybe a shady sales man too. I have never had coolant get in the oil with a low liner. an easy way to check for compression in the radiator is to fill it all the way up, run the engine. If it is real bad it will get alot of bubbles right away. if it is a small compression leak it will have to heat up first. Another thing that you can do if the radiator has that 1/8" pipe plug in the top of the radiator is to connect a hose to it, fill a bottle with water, put the hose in the bottle and watch for bubbles. This is my favorite way because it allows you to stall the machine with out loosing alot of coolant.
Ive got them down to half the the asking price so even if does need an engine rebuild it will be pretty good value compared to anything else ive found here in Aus. Thanks to all for your thoughts and ill keep you updated on what i find. Cheers
oil in the rad what about the trans cooler,is oil black or cleanish
It was black as night
nice trick mate, good way to get her on full stall and show any leakage!