B7100 Oil in Coolant

Saskstallion

New member
Mar 9, 2018
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Edmonton, AB, Canada
Hi All. I'm brand new to the forum, and brand new to Kubotas.
I'm looking at buying a 1980 B7100, and the person selling it has confirmed that there is oil in the coolant, but the tractor is still running smooth...
Before I get too far in negotiations on price, I'm wanting to know if anyone has any opinions on if this will be a big problem that I'm buying, or could it be as simple as just a head gasket or frost plug replacement.
I've been told that worst case scenario would be a cracked head, and a hefty repair bill.
Any help would be very much appreciated!
 

North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
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Sandpoint, ID
Oil in the coolant is VERY VERY rare, it almost always goes the other way.
Some pressure testing would need to be done, and because it doesn't have a water pump it's fairly easy to do.
It's highly unlikely that it's a Head gasket issue or freeze plug issue, as that would put coolant in the oil not the other way around.
A bad head gasket and or cracked head usually presents itself as water in the piston and hydro locking.
The only plausible way for oil to get into the coolant would be ????? .... I really can't think of one. :confused:
 

Beaudeane

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MX5800, LA1065, BH92, BB72X, RT72.40, EA 60 in grapple, county line auger
Mar 9, 2018
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Dalton, Ga
Are u sure it’s oil, could it be fuel? Smell it & u will know. Had that issue in my Freightliner once with fuel in the coolant. It turns coolant black. Ended up being injector cups. Had that fixed & good since then but I also thought it was oil in the coolant by how it looked. 500k miles later & the resovoir is still stained dark & its been flushed several times. Don’t know how similar a Detroit diesel is to a Kubota but I’d look at that option if the antifreeze is black & smells like fuel.
 

Rodnok

Member

Equipment
B7100hst, MMM, Box Scraper, FEL make unknown, adapted and resurrected from junk
Dec 28, 2015
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6
chattanooga, tn
Oil in the coolant is VERY VERY rare, it almost always goes the other way.
Some pressure testing would need to be done, and because it doesn't have a water pump it's fairly easy to do.
It's highly unlikely that it's a Head gasket issue or freeze plug issue, as that would put coolant in the oil not the other way around.
A bad head gasket and or cracked head usually presents itself as water in the piston and hydro locking.
The only plausible way for oil to get into the coolant would be ????? .... I really can't think of one. :confused:
My personal experience has been that oil in water is either blown head gasket or cracked head or cracked block. That said My experience has been in either car or boat motors. Pressure test the engine is the only way to find out the problem. If the problem is the head gasket that is a simple problem not too costly. head or block cracks are expensive.