Bertram 35 Tranmission Temp

maverick · Post by **maverick** » Tue Jun 07, 2016 3:26 pm

Hi There, just recently purchased a 35 and having some issues with the temp alarm going off on the transmission oil coolers. I have just replaced both oil and tranny coolers as the survey deemed them past useful life. Since then having issues with the trannys running hot and the alarm going off.. looks like one of the sending units is a 190F and the other is a 230F. the 190 goes off after about a hour of running at 3200 rpm and the 230 shorlty there after. not pushing the boat hard but wondering if anyone has any experience with a similar issue of not getting enough cooling? thanks Matt Maverick Bertram 35

maverick · Post by **maverick** » Tue Jun 07, 2016 3:28 pm

I guess I should've mentioned running Mercruiser 427 (325 HP) with Velvet V Drive model AS17-72C on a 73 Bertram. Thanks

h2ojst · Post by **h2ojst** » Wed Jun 08, 2016 4:53 am

Hi Matt, Have you taken the seawater pumps apart and rebuilt them yet? Start with the incoming water & make sure nothing is wrong there. What are the engine temps? The two senders should both be the same & a Mercruiser dealer could probably tell you which one is incorrect. If the engines are also running hot, I'd pull the heat exchangers & have them cleaned & pressure tested. The trany coolers are all seawater fed, so if their not getting a good water flow either in or out the transmissions will overheat. Last but not least, change the tranny fluid & start fresh there as well. The heat will break down the fluid.

maverick · Post by **maverick** » Wed Jun 08, 2016 6:30 am

Thanks Joe, haven't taken apart the pumps yet, the engines themselves are not actually running hot all. the heat exchangers were rebuilt when I replaced the oil coolers. will try changing the fluids and starting new. when the mech came back and checked the cooler and we went for a burn the transmission fluid was going in around 130 and coming out 110 so the cooler was doing what it was supposed to, it just seems at the higher RPMs it is still over heating.. or maybe just a touchy sensor, but that wouldn't explain why both ended up going on the last big run.. hmmm.. thanks

IRGuy · Post by **IRGuy** » Wed Jun 08, 2016 8:21 am

Maverick The first thing I would check is the trans cooler raw water side for obstructions. Often when a raw water pump impeller gets torn apart the pieces of rubber get stuck in the inlet side of the heat exchanger (cooler) and restrict raw water flow. You can check the trans actual temp with an infrared thermometer available at a lot of building supply stores for less than $100. I bought one from Grainger several years ago when I thought my engines were running hot. it turned out that both temp sensors were bad. As a check I have opened up the trans coolers and found several pieces of rubber... not enough to restrict raw water flow significantly but it could be a start. You really don't know what the previous owner had experienced before you bought the bot.