Bigjohn4300 Posted October 28, 2021 Share Posted October 28, 2021 2004 granite 300 AI/Allison combo having overheating a issue. When tagging the excavator (82k gross), water temp climbs to the edge of the red when accelerating from a dead stop to 45, but starts falling fairly soon once throttle backs down (maintaining 40-45). At lower weights, never gets close to red. Radiator rodded out a year or so ago, 50/50 antifreeze changeout yearly, fan clutch appears to be pulling good, Allison verified no trans issues(trans temp stays mid range)...what else should i be looking at? Possibly the cooling package is marginal(seems like i read something on BMT about the 300 hp motors having a “economy” cooling system available for non A/C trucks with a smaller water pump???) This truck was a non-A/C mixer truck up north originally, maybe a marginal radiator with A/C and our ambient temps? any ideas? Quote Link to comment https://www.bigmacktrucks.com/topic/68594-300ai-cooling-issues/ Share on other sites More sharing options...
Mackpro Posted October 29, 2021 Share Posted October 29, 2021 Might be a clogged oil cooler inlet screen . I remember the AC engines having them but was unsure if the AI engine had them . This bulletin says both engines had them . http://www.engineprofessional.com/TB/TB011816-1.pdf Quote Link to comment https://www.bigmacktrucks.com/topic/68594-300ai-cooling-issues/#findComment-482050 Share on other sites More sharing options...
Mackpro Posted October 29, 2021 Share Posted October 29, 2021 The AC and AI engines have 2 thermostats , if one to stick it can cause overheating. Also , if the engine does not have a coolant filter or the coolant SCA levels are out of range , it can cause corrosion in the cooling system. Pull the water pump off and look into the aluminum housing that’s bolted to the block . It should be smooth. I’ve pulled several water pumps off and had severely pitted housings that caused overheating. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68594-300ai-cooling-issues/#findComment-482051 Share on other sites More sharing options...
Bigjohn4300 Posted October 29, 2021 Author Share Posted October 29, 2021 Ok ill check that this weekend, and no it doesn’t have the filter/conditioner Quote Link to comment https://www.bigmacktrucks.com/topic/68594-300ai-cooling-issues/#findComment-482070 Share on other sites More sharing options...
Mackpro Posted October 29, 2021 Share Posted October 29, 2021 Somewhere around 2002 Mack made the coolant conditioner filter an option. That $50 option cost way way more 8-10 years down the road, Quote Link to comment https://www.bigmacktrucks.com/topic/68594-300ai-cooling-issues/#findComment-482074 Share on other sites More sharing options...
Bigjohn4300 Posted October 30, 2021 Author Share Posted October 30, 2021 Yea the company that originally bought her had her bare bones, no ac, no lateral stabilizer, no passenger seat etc Quote Link to comment https://www.bigmacktrucks.com/topic/68594-300ai-cooling-issues/#findComment-482098 Share on other sites More sharing options...
Bigjohn4300 Posted October 30, 2021 Author Share Posted October 30, 2021 Are you familiar with the different water pump im referring to? A different pump available on the 275 and 300s as a economy option? Quote Link to comment https://www.bigmacktrucks.com/topic/68594-300ai-cooling-issues/#findComment-482099 Share on other sites More sharing options...
Mackpro Posted October 31, 2021 Share Posted October 31, 2021 For the ASET engine family I only remember there being 2 different water pumps. One of the AI engines and one for the AC engines. The pulley diameter was the only difference. It was very easy to put the wrong one on and saw it happen quite a few times. The belt might be a little tight or loose but they will easily bolt up and cause cooling issues 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68594-300ai-cooling-issues/#findComment-482168 Share on other sites More sharing options...
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