Fiat AT7C dozer blowing oil from exhaust after oil change

[Gazzaboy]

Have just purchased this dozer and when I first looked at her she ran great ie. no smoke but the crankcase oil level was low, only up to minimum on dipstick. When I got her home I did a oil change and filled with the amount as described in the manual. Now when I start her she blows copious amounts of oil and blue smoke from the exhaust pipe. Does this occur if over-filled? I don't know if the dipstick is original but looks like it is. Any advice would be greatly appreciated.

 

[Former Wrench]

A rough rule of thumb is to measure from one inch below the pan/block level to the top of the dipstick tube. That should be close to the full level.

 

[Nige]

No idea if it's the case on this particular machine, but are there different oil levels on the stick for "engine stopped & oil cold" & "engine at low idle and operating temperature"...?

 

[Pathull]

doesn't sound good, normally if you overfill a crankcase you get oil maybe coming out of your engine breather, not exhaust! good luck but

 

[ianoz]

What sort of oil did to put in it ,Recommended oil is a straight 30 grade ,it could be that it does not like a mutli grade oil

 

[Gazzaboy]

Thanks for all the responses guys. Firstly the dipstick seems like the original, has only min and max markings. I did put a multigrade oil in in the first instance but have dropped that out. Seems to be improving but I think it's because the oil level is dropping. I spoke to a mechanic in town who has worked with these old girls and he has experienced this before. He reckons to let her find her own oil level and keep her at that and will do no harm. What are your thoughts on that?

 

[Queenslander]

We owned one of these but never experienced this problem, always topped oil up to max. mark.
Unrelated, but sometimes when leaning on a stubborn tree with the pusher, if you stalled the motor the tree would push the tractor back before you could throw the clutch.
Turning backwoods, the motor would throw out a gob full of oil from the oil bath air cleaner.
Cheers, Greg

 

[Garrie Denny]

I was going to suggest worn valve guides on the exhaust stems,but from memory your motor (70c1) don't have them,so I cat really say unless your motor does have valve guides.

 

[Garrie Denny]

Queenslander:that sounds right,motor turning backwards is going to send pressure to the inlet valves and on to the filter,they hold about 1 litre or there abouts.

 

[hardtail]

I have had a couple automotive engines in past years that acted like this with level, they would push oil until they found their own mark. I think the breathers were ok but as I recall the engines of mine that did that weren't in their first flush of youth... I hope that's all it is, I would really keep an eye on it if it likes a lower level, your breathers and air filtration ok?

 

[Gazzaboy]

I did clean the oil bath filter and filled to mark. Not sure about the breather. The only one I can think of is on the filler so I will check this first chance. The dozer is about a 1970 model I was told so not in her prime

 

[Garrie Denny]

You will fid it has the same 4 cylinder motor as my Fiat 70CI I think they were 1 or 2 models apart.

 

[Garrie Denny]

Better still go to the Old Iron Forum, there is a dedicated site for the earlier Fiat Dozer/crawler tractor, which yours is a variant.

 

[ianoz]

Mate , you said filled with the amount shown in the Manual .,Does it show as the right amount on the Dipstick .Thinking could possibly be a misprint in the manual .
Also it could be doing what the americans call Slobbering .If it is left idling , or on light engine loading the bores could glaze up .
Put it into a bit of hard work and see if it clears up .

 

[Garrie Denny]

Did you remove the 2 filters when you changed the oil ? If not, then you have overfilled by about 2 litres into the sump. that's what they hold approx. As ian says GO BY YOUR DIP STICK,ON LEVEL GROUND FOR CORRECT OIL LEVEL.

 

[Garrie Denny]

I HOPE THE MECHANIC IN TOWN, who advised you its O.K. to let an engine find its OWN level of oil in the sump (how does that work? must be a latest invention, its definitely not on my dozer) and run low,damaging same will be happy to do all repair work for NOTHING 2.

 

[balls2go]

Does this engine have a turbo? A few weeks ago, I had a tractor start smoking blue at idle and blowing oil out the exhaust pipe. Changed the turbo and fixed it. Suppose the seal on the exhaust side of the turbo was leaking under low boost situations.

 

[Garrie Denny]

No Turbo on this engine.

 

[charliebuckshot]

gazza got any pics of the old girl?

 

[ianoz]

Charlie , there is photos of afew diferent 70CIs here in OZ on this thread .
https://www.heavyequipmentforums.co...5-Fiat-70CI-Repairs-modifications-and-stories