Dieselfixer Posted December 5, 2012 Share Posted December 5, 2012 (edited) Hi All;I have a problem with a RD690S that is got me going a bit crazy. The truck came in with low oil pressure. I checked the oil level and it was way up on the stick and Very thin. I was not sure if the driver may have added hydraulic oil to it instead of 15/40 motor oil so I changed the oil and filters and the oil pressure was back to normal.About 9 days later it did it again, oil very thin, way up on the stick and low oil pressure. I sent a oil sample out expecting to have it come back with a load of fuel in it. The sample came back with <1.0 fuel, < 0.1 water, and neg glycol. Anyone have any ideas on this problem? I'm going to send another sample to a different lab and see if it comes back the same as the 1st sample. Thanks Edited December 5, 2012 by Dieselfixer Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/ Share on other sites More sharing options...
thomastractorsvc Posted December 5, 2012 Share Posted December 5, 2012 if it not fuel or antifreeze, they put something in it, maybe they have bulk oil and its missed marked??? Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-149490 Share on other sites More sharing options...
1958 F.W.D. Posted December 5, 2012 Share Posted December 5, 2012 I use Giles and Ransome Caterpillar's lab in Bensalem, Pa. (www.ransome.com I think) for my antique Waukesha gas engine. They will analyze any make and model of engine, and send you the report and usually tell you what to look for if problems come up. IIRC it's 16.95 for one analysis kit- Call them with your credit card handy and they send you the kit- a sample bottle, an overpack bottle, a long thin piece of flex tube to draw the sample from the dipstick tube, and a pre-paid UPS envelope to ship it back to them. The price includes the analysis. See what they come up with, good people. Quote TWO STROKES ARE FOR GARDEN TOOLS Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-149498 Share on other sites More sharing options...
Dieselfixer Posted December 5, 2012 Author Share Posted December 5, 2012 Thanks for the replies, I sent the 1st sample to Castrol's Labcheck. I sent another today to the local Caterpillar dealer here. I'll see what it comes back as. I do have a bulk oil tank here but I have 17 other trucks running on the oil from the same tank and they are fine. Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-149508 Share on other sites More sharing options...
rick harper Posted December 5, 2012 Share Posted December 5, 2012 Make sure you have the right part number dipstick. That doesnt explain the thin oil. Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-149520 Share on other sites More sharing options...
1958 F.W.D. Posted December 5, 2012 Share Posted December 5, 2012 Thanks for the replies, I sent the 1st sample to Castrol's Labcheck. I sent another today to the local Caterpillar dealer here. I'll see what it comes back as. I do have a bulk oil tank here but I have 17 other trucks running on the oil from the same tank and they are fine.still might want to run a sample of the bulk oil tank......just in case.... Quote TWO STROKES ARE FOR GARDEN TOOLS Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-149540 Share on other sites More sharing options...
farmer52 Posted December 5, 2012 Share Posted December 5, 2012 Is the truck using bio-Diesel fuel? If so, bio fuel dilution will not show up using the "normal" fuel check. What is the viscosity (cSt)? Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-149542 Share on other sites More sharing options...
staxx Posted December 6, 2012 Share Posted December 6, 2012 What year is this the e-tec engines had issues with the fuel supply pump shaft seal blowning out and pouring fuel into oilpan also there is a fuel galley plug behind front cover that gets loose and leaks fuel also sometimes. Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-149628 Share on other sites More sharing options...
staxx Posted December 6, 2012 Share Posted December 6, 2012 Sorry now I see the year in the title have seen the lift pump on these go letting fuel into oil . Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-149629 Share on other sites More sharing options...
mclow Posted December 9, 2012 Share Posted December 9, 2012 Its more than likely losing powersteering fluid through the powersteering imput shaft seal on the pump and dumping fluid into the engine oil. Most guys just keep adding powersteering fluid to the reservoir thinking they have an external leak. If this is the problem it is a pretty easy fix around about 100 bucks. Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-150242 Share on other sites More sharing options...
staxx Posted December 9, 2012 Share Posted December 9, 2012 If it was powersteering it shouldnt lose oil psi because powersteering uses engine oil on the older trucks. Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-150252 Share on other sites More sharing options...
oilburner Posted December 9, 2012 Share Posted December 9, 2012 Its more than likely losing powersteering fluid through the powersteering imput shaft seal on the pump and dumping fluid into the engine oil. Most guys just keep adding powersteering fluid to the reservoir thinking they have an external leak. If this is the problem it is a pretty easy fix around about 100 bucks.Yeap i had this happen once, but not with a mack, it was a mack truck but a cat engine, but we used engine oil in the power steering and it had a small leak, it took us a while to figure out were the oil was coming from, the driver said the engine was pushing oil out the dipstick and our frist thougth was it needs overhauled, but when he pulled in we herd the pump wineing it was almost dry, i had a freind that told me to check the pump and he was right fixed the problem. Our 98 mack has looks like hydrolic oil in the power steering i don't know put it looks thin and has a greenish tint to it. Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-150261 Share on other sites More sharing options...
mclow Posted December 12, 2012 Share Posted December 12, 2012 If it was powersteering it shouldnt lose oil psi because powersteering uses engine oil on the older trucks.I bought mine at auction and thats what happened and it smoked the engine because the previous owner used ATF in the powersteering. After I overhauled it I went back with engine oil. Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-150711 Share on other sites More sharing options...
mclow Posted December 12, 2012 Share Posted December 12, 2012 If it was powersteering it shouldnt lose oil psi because powersteering uses engine oil on the older trucks.Also, the crankcase is probably getting so full that the crankshaft is "whipping" the oil, aerating it causing it to lose oil pressure Quote Link to comment https://www.bigmacktrucks.com/topic/28699-95-rd690s-engine-oil-problem/#findComment-150713 Share on other sites More sharing options...
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