Bbo44 2 #1 Posted April 19, 2023 My 520xi with CH20s has always ran hot and even hotter this year. Everything seems to be fine, I just cleaned all around the motor in hopes it helps but want to add an oil cooler. Plugs look fantastic after a summer of mowing. I am seeing 3 different versions and not sure if they all would work or if just one. Here are the 3: I see in the manual the first one is on the Ch26 and second CH25. The 1st one looks like a pain to install and is the most expensive. You have to also cut a big hole in the one shroud on the engine to allow air to pass over the cooler. I would like to go the cheapest route as anything is better than what I have now. Bonus points if you have part numbers for either of the cast coolers. I found a few, but all seem to have different part numbers for some reason, even from the number casted into the back of the housing. Also if there is a part number for the threaded nipple adapter as some of the coolers come without it. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,048 #2 Posted April 19, 2023 This may help 2 Share this post Link to post Share on other sites
Wild Bill 633 846 #3 Posted April 19, 2023 (edited) 9 hours ago, Bbo44 said: The 1st one looks like a pain to install and is the most expensive. You have to also cut a big hole in the one shroud on the engine to allow air to pass over the cooler. I have installed (2) of the first kind. Not a bad install at all. The hole cut in the blower housing is to allow a portion of the air flow generated by the flywheel fan to pass thru the oil cooler to cool the oil. Just like a radiator on water cooled engine. IMHO a better design than the other (2) which act more like a heat sink using stagnant ambient air. Edited April 20, 2023 by Wild Bill 633 1 Share this post Link to post Share on other sites
kpinnc 12,099 #4 Posted April 20, 2023 2 hours ago, Wild Bill 633 said: Just like a radiator on water cooled engine. IMHO a better design than the other (2) which act more like a heat sink using stagnant ambient air. Agreed 100%! 2 Share this post Link to post Share on other sites
Wild Bill 633 846 #5 Posted April 20, 2023 You can also add the blower housing access panel kit, Kohler P/N 25 755 20-S which allows you blow compressed air into the blower housing area in order to keep clean. 1 Share this post Link to post Share on other sites
Bbo44 2 #6 Posted April 20, 2023 17 hours ago, Wild Bill 633 said: I have installed (2) of the first kind. Not a bad install at all. The hole cut in the blower housing is to allow a portion of the air flow generated by the flywheel fan to pass thru the oil cooler to cool the oil. Just like a radiator on water cooled engine. IMHO a better design than the other (2) which act more like a heat sink using stagnant ambient air. Thank you! Going to look for a good shape second hand cooler in the first style if I can get it for the right price. Seems easier to clean and would give me an access point to cleaning behind that plastic guard without pulling the Engine. I've heard the entire kit isn't necessary, but just the cooler loop and you can make it work. However, I'm finding tons of part numbers for what looks like all the same thing. 2 hours ago, Wild Bill 633 said: You can also add the blower housing access panel kit, Kohler P/N 25 755 20-S which allows you blow compressed air into the blower housing area in order to keep clean. should have come from factory with these! Might have to add them now that I already have the motor out. Share this post Link to post Share on other sites
