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Onan code 33

Yahoo Message Number: 97365
Onan Code 33

Just thought I'd pass this on. My Onan HDKAK, SPEC H started shutting down again, and this time I was getting a codes 33, overheat. Turns out is was the overheat sensor. I tried replacing it, was able to remove part of it, bit the bottom probe half of the sensor broke off and stayed inside the shroud/flange. Okay, no problem, I'll just change the shroud too. While removing I realized that the whole front of the engine gearbox had to be removed to get the last shroud bolt off. Way to go Kabota! FIREUP on rv.net said he was able to remove the last shroud bolt by removing the engine head. Since my Onan is side mounted, I Decided to take it in and let Onan do it after we got back to FL. During discussion with brother-in-law, he suggested to try an EZ-out. Wala! It came right out! Runs good now, plus no more white smoke and hard starts during cooler weather. Apparently that sensor also tells the ECM the temperature so it knows how long to heat the glow plugs. Mine wasn't heating the glow plugs. Before, As soon as I hit the start button the starter engaged without heating the glow plugs which made it really hard to start in cooler weather with lots of white smoke (unburned diesel). Now when I hit the starter button, there's a delay with an audible clicking sound while the glow plugs heat up, then the starter engages. This hard-start issue started about 100 hours ago, and progressively got worse. So, if you're getting hard starts with white smoke, its a telltale sign that your overheat sensor is going bad and you will eventually have problems keeping it running in warm/hot weather. Happy trails...

Larry, 03 Allure, 30856.
 

Re: Onan code 33

Reply #1 –
Yahoo Message Number: 97368
I removed the coolant temp sensor on the 7.5KW Onan on my previous coach. After reading about how corrosion can freeze it in the housing, I heated mine briefly with a propane torch, then sprayed it well with Deep Creep. Mine came out easily.

Gary

'07 Allure 470 #31578