Author Topic: 91 Suburban over heating question  (Read 127 times)

Offline Deercreekfarm

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91 Suburban over heating question
« on: September 07, 2019, 05:28:52 PM »
So the temp started rising on the burban. Noticed a small leak in the radiator so replaced it with a new one. Still no change, replaced thermostat and no change. Replaced the fan clutch and again no change. Yanked of the water pump went to get a new one and nothing matched it. Everything for a 91 v2500 4x4 6.2 Diesel did not match. Finally a pump for an 85 Suburban fit. Problem now is small leak from between the face plate and the engine. Yank it off, wipe everything down, new gasket, bolt it back on multiple times and still a small leak.

Anyone had this problem? Any tricks or secret fix?

Also now I have to track down the VIN on the engine block and figure out whatís going on with only the 85 water pump matching up. Only thing I can think is previous owner replaced engine block and put all the 91 electronics on it.

Offline MIKE S

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Re: 91 Suburban over heating question
« Reply #1 on: September 07, 2019, 06:44:16 PM »
91 is reverse rotation. 85 is standard rotation. Make sure it matches your set up

Offline Deercreekfarm

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Re: 91 Suburban over heating question
« Reply #2 on: September 07, 2019, 09:35:13 PM »
91 is reverse rotation. 85 is standard rotation. Make sure it matches your set up

Yeah like I said now I have to do some research because when I picked up the 91 water pump from the parts store it looks almost the same as the one that came off the engine but the internal channels look a little different and the bolt pattern is different. So we tried an older one 85 and it matched perfect to the pump that came off of the engine.

So Iím thinking the previous owner swapped motors or is there a chance that the front plate (not sure of actual name) that the water pump bolts to then that plate bolts to the front of the engine, is there a chance these are interchangeable over multiple years?

But then again I was having an overheating issue before so Iím at a loss.

Offline Deercreekfarm

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Re: 91 Suburban over heating question
« Reply #3 on: September 10, 2019, 10:01:49 PM »
At a total loss!!!!!!   

New thermostat, new radiator, new water pump and sheís still overheating. Does anyone have any ideas or suggestions?

Could a clogged heater core make the engine overheat?

Offline Irish_Alley

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Re: 91 Suburban over heating question
« Reply #4 on: September 10, 2019, 10:23:34 PM »
warped head or blow head gasket would cause it to overheat. if it ran out of coolant and over heated it might have did more damage to it. my cummins had an overheating problem but it was blowing coolant out of the overflow tank. never replaced anything trying to troubleshoot it. unhooked the turbo and drove it without any boost and it was gutless and i was on it easy but it didnt overheat. replaced the head gasket and no more problems. take the rad cap off and start the truck, do you notice bubbles in the coolant when the engine is running? let it warm up with the cap still off and look for bubbles. normally the coolant will have some bubbles due to the flow but you might notice more than normal amount of bubbles. also a bad rad cap will cause it to overheat
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Offline Deercreekfarm

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Re: 91 Suburban over heating question
« Reply #5 on: September 10, 2019, 10:33:35 PM »
warped head or blow head gasket would cause it to overheat. if it ran out of coolant and over heated it might have did more damage to it. my cummins had an overheating problem but it was blowing coolant out of the overflow tank. never replaced anything trying to troubleshoot it. unhooked the turbo and drove it without any boost and it was gutless and i was on it easy but it didnt overheat. replaced the head gasket and no more problems. take the rad cap off and start the truck, do you notice bubbles in the coolant when the engine is running? let it warm up with the cap still off and look for bubbles. normally the coolant will have some bubbles due to the flow but you might notice more than normal amount of bubbles. also a bad rad cap will cause it to overheat
Thanks for the info. I will check that out.