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Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather


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  #21  
Old 09-13-2018, 09:57:34 AM
kwfiggatt kwfiggatt is offline
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

I think I'd invest in an oil temp gauge. You can get a cheapie for less than $10 on the 'bay... Maybe even cylinder head temp and oil pressure too...

That'd at least give you some good data as to what's going on, rather than the dumb messages from the trouble codes...

Kevin
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Old 09-13-2018, 02:38:53 PM
Eric.S Eric.S is offline
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

Quote:
Originally Posted by 2011itascanavion View Post
Should I actually feel some air "suction" at the inlet?

At the cooling air inlet? you should feel "wind" going in

Eric, i'm having trouble finding the parts you're referencing on the HDZAA (Spec A-E) Onan Parts Manual. I don't see any parts starting with NR, they are all part numbers like 123-2399 (my crankcase breather).

I referred to the Hatz parts list PDF in your post nr 12
nr as for number in the drawing not the part order number.

One other question just came to mind. If this is actually a Hatz 1B20V generator, is there a resource on this board for Hatz service manuals so I can see how that crankcase breather is supposed to be installed?
Google for workshop manual for Hatz 1B30V, you can find it looking at the parts list drawing and the engine.

Sorry,not the workshop manual but where the breather is about to be located
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  #23  
Old 09-13-2018, 04:38:47 PM
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

If able to do so, It could be a good idea to wrap the breather/oil separator with some sort of heat shielding. That little set is probably jammed so tight into the RV that it might not be possible but worth a try. https://www.amazon.com/010127-Titani...002R4XLNU?th=1

Here is another company that makes silicone sheathing tube in various sizes: https://www.heatshieldproducts.com/fire-shield-sleeve

ALSO, Due to the high heat this engine is seeing, I'd highly recommend, if you are not already using it, full synthetic diesel rated oil in the engine.
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Old 09-13-2018, 05:37:19 PM
Eric.S Eric.S is offline
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

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Originally Posted by Motorhead View Post
If able to do so, It could be a good idea to wrap the breather/oil separator with some sort of heat shielding. That little set is probably jammed so tight into the RV that it might not be possible but worth a try.
Question is, is the breather melting due to high oil temp or high surrounding temp. might be both, everything pushed to the limit, housing, technical specs ect.
As already said, measuring is knowledge.
Fully synthetic oil is better for the engine but makes no difference in high oil temp or low pressure shut down. As i understood it runs OK in winter temperatures, so not enough cooling capacity.
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Old 09-13-2018, 07:15:18 PM
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

Eric, I guess one would have to inspect the part to see if the deformation is from the inside or the outside. From the pictures, it looks from the outside but I could be wrong. The engine looks to have a cartridge oil filter. If it had a conventional spin on type, the owner might be able to get a "Sandwich" type adapter that fit between the filter and the engine block, then run oil lines to an external oil cooler. Forced air venting of the generator cabinet with an external blower might help too.
The obvious issue the owner would have with replacing it with another on-board generator set is fuel source. The mercedes being diesel limits liquid fuel to diesel. The other option would be propane so long as the rigs LP tank is adequate enough.
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Old 09-16-2018, 05:04:39 PM
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

Did not searched for the service manual yet, but this is a EPA4 engine, it might have some kind EGR system or how you guys call it, return some of the exhaust gas to the air inlet to reduce emission. If this is injected in this breather system it can get nasty hot when something fails.
This breather valve looks like a spring loaded valve, if it's not closing properly ??
just a guess.
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Old 09-21-2018, 03:01:55 PM
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

Download Hatz user manual "ebook_BA_1BV_43380279_EN"
When your engine serial number starts with 175 the engine has an exhaust DOC, diesel oxidation catalyst, when this thing is partly blocked it can cause severe overheating the engine, give high pressure on the crankcase and due to that overloading and over heating the breather system.
I haven't said this, get rid of the DOC exhaust and mount a Hatz exhaust without. (oil pressure at 3000 rpm, 2.5 bar at 100 degrees C)
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Old 09-21-2018, 03:50:23 PM
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

Eric has a VERY valid point!
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  #29  
Old 09-26-2018, 08:54:31 AM
2011itascanavion 2011itascanavion is offline
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

Just an update for everyone. We installed the new crankcase vent yesterday. The discharge hose that snakes behind the air filter assembly was completely melted along with everything else (see prior pics). I started it up, put it under load, watched it run for 15 minutes, and went into the house for about a 1/2 hour. When I returned the engine was shut down, there were no codes, and oil was burning off the engine again. good times. I have one of those temperature lazer pointers and the temp on the crankcase was 260 degrees. We had changed the oil and cleaned the oil filter also (put the $15 a quart onan oil in).

So, guess I'm back to square one minus the $173 for the part and $250 I paid the guy to diagnose the issue and install the part. To his credit he said before he started that he didn't think installing the new part would correct the high temperature issue but I wanted to at least rule it out.

Suggestions anyone? This high temp thing has me baffled. The engine did turn over again so it hasn't seized up due to the high temp. I was going to start it back up and leave the cover off but I'm probably going to at least have to replace that hose behind the air cleaner again because I think that melted again and that's why oil was burning. The remainder of the crankcase vent doesn't appear to have melted. I have no idea what caused it to shut down because there is no code surprisingly. Who knows, maybe the sensor is toasted.

I'm in Michigan but thought I might call Lichtsvinn to see where they send their RV's with diesel generator issues. I'm hoping there is a Cummins service shop that has a tech that has some skill in diagnosing and correcting this issue. I have no confidence in our Cummins dealer here because I've been dealing with the issue since I bought the RV new....(have the letters to Winnebago to prove it).

Eric, I just saw your post and it sure seems like what I experienced last night. I'm not sure what the "an exhaust DOC, diesel oxidation catalyst" is but I'm printing the manual you listed so I'll see if I can figure it out.

Eric, where is that DOC on the engine?
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  #30  
Old 09-26-2018, 09:58:16 AM
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Default Re: Cummins Onan Diesel Generator Model 3.2HDZAA-6508B Crankcase Breather

Eric,,, you're thinking it's putting hot exhaust right into the crankcase? That's ugly :-(
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