Hi all, We have a Komatsu 85-18 bulldozer with a cummins 855 engine. The engine has recently started foaming up the coolant (we use fleetguard rust inhibitor and rainwater) out of the radiator cap and over the bonnet after approx 15min of operation. A ridiculous amount of foam comes out and can take up to half an hour to dissolve once engine is shut down. We (a mate CAT dozer mechanic) pulled the heads off the engine and sent them away for testing and they found 3 injector tubes were buggered and replaced them, otherwise heads were ok. Also heads were machined. We replaced heads and started engine up today and problem still exists. Any ideas where to go next?? thanks alot Horace
How’s the temperature running
How many hours on the bottom end? Any contamination? Does it stink of coolant or oil? Are you losing any other fluids?
Check coolant level is not to high before starting , it has to go somewhere . There should be a relief valve for the excess coolant to leave and not around the cap . Check both cap and relief valve . Is the dozer running hotter than it used to . I think you jumped for the worst most expensive options first .
Dozer works pretty hard pulling chain clearing scrub there has been no change in temperature behaviour . It will overheat 100c in summer (40 degree c days) but so does the other dozer it works with. i have no history on engine bottom end. will have a look at relief valve thanks. forgot to mention there was contamination leaking out of turbo either fuel or oil prior to checking heads. thanks
Have you had coolant tested to see what’s in it
the only way a radiator can foam like he`s describing is if its being pressurized from some where . being an 855 cummins and just having the heads done i`d say the (liners) should have been pulled and checked while the heads were off . my guess (cavitation) pits forming , check for coolant in oil
That's kinda what I was eluding to in asking how long the bottom has been in service. I'm a bit put off by "foaming" There has to a contaminant causing this foaming. Coolant when overheated will percolate, bubble and boil, not foam. At this point , I'd suggest getting a box of cascade dishwasher soap. Drain and fill with water several times. On the last time, throw half the box in a 5 gallon pale, suspend in water and add that to the mix. Let it run for a good while, maybe a half hour to an hour, at full throttle with the radiator partially obstructed. Monitor coolant temp. After a while , while it's running, bring her back to idle, open drain cocks and start flushing with fresh water til clean water runs out everywhere. As shes cooling down you can shut it off, while the water continues flushing. When everything is clear, let it all drain and fill with fresh mix. I'm guessing your cups allowed fuel in the coolant and your dealing with trapped fuel here and there.
I'd bet on liners myself
Hi Everyone, sorry it has taken so long to reply. Status report. We removed heads on engine and sent away for checking. seems that liners were the issue. It is back together now and going well. Thanks alot
Glade to hear it was finally fixed and thanks for closing the door on the problem!