Dewitts Fan
Thread Starter
Burning Brakes
Joined: Mar 2019
Posts: 843
Likes: 149
From: Iowa
Dewitts Fan
I have a new Dewitt double row radiator and all new hoses sitting in my basement waiting on the Iowa Deep Freeze to lift and do the install in April when I do not have to worry about distilled water freezing in my engine block over night with the flush and install. I have been looking at the Dewitt 1990-1996 fan upgrade, I was ready to order but I went out and inspected my 95 and found that the fan on the right side is lower to accept the A/C Accumulator. Has anyone installed these fans and is there clearance for the Accumulator ?
Thank You
Hawkeye56
Thank You
Hawkeye56
Safety Car
Joined: Mar 2017
Posts: 4,202
Likes: 1,323
From: LeClaire Iowa
It is just my opinion but I don't think the fan "upgrade" is worth the money or grief installing it. You can replace your two fan motors for 35 bucks each and get back to factory air flow. I think I read that the fans turn off at 35 MPH as running over that speed actually slows the airflow. Dan
Thread Starter
Burning Brakes
Joined: Mar 2019
Posts: 843
Likes: 149
From: Iowa
It is just my opinion but I don't think the fan "upgrade" is worth the money or grief installing it. You can replace your two fan motors for 35 bucks each and get back to factory air flow. I think I read that the fans turn off at 35 MPH as running over that speed actually slows the airflow. Dan
I have been thinking the same thing . I have found GM replacement motors on line.
Did you replace just your fan motors?
Thank you
Hawkeye56
Safety Car
Joined: Mar 2017
Posts: 4,202
Likes: 1,323
From: LeClaire Iowa
Thread Starter
Burning Brakes
Joined: Mar 2019
Posts: 843
Likes: 149
From: Iowa
Yes, everything else was reused after extensive cleaning. I did not use the expensive GM replacement motors. I used Rock Auto ones. I used the most expensive up to it took a giant jump to the GM ones. The increase in airflow was noticeable. Dan EDIT: I also installed a Dewitts single row.
Thank you
Hawkeye56
Oh I almost forgot to mention that my engine is not stock, LT4 Hot Cam, Heads and headers.
Thread Starter
Burning Brakes
Joined: Mar 2019
Posts: 843
Likes: 149
From: Iowa
Safety Car
Joined: Mar 2017
Posts: 4,202
Likes: 1,323
From: LeClaire Iowa
Since I live in Iowa I have the AC on most of the time. We don't have LA type stop and go. In our stop and go I have seen it get to 206 degrees. If it got to 230 I would freak out and probably shut it down. Dan
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Thread Starter
Burning Brakes
Joined: Mar 2019
Posts: 843
Likes: 149
From: Iowa
As I live in Iowa also we share the same temperature. My stop and go is when we are in Quincy IL. Going down Broadway. About the same as the Quad Cities.
Instructor
Joined: Jan 2021
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I find the stock radiator fan works fine just the temperature is set way too high. I put a 210 degree switch in and now it doesnt ever get too hot.
FWIW its probably also fine to let it hit 230...lots of C4s have made it many decades doing that. But no reason to chance it in my mind when we're not trying to hit microscopically better emissions numbers like GM was.
FWIW its probably also fine to let it hit 230...lots of C4s have made it many decades doing that. But no reason to chance it in my mind when we're not trying to hit microscopically better emissions numbers like GM was.
Thread Starter
Burning Brakes
Joined: Mar 2019
Posts: 843
Likes: 149
From: Iowa
I find the stock radiator fan works fine just the temperature is set way too high. I put a 210 degree switch in and now it doesnt ever get too hot.
FWIW its probably also fine to let it hit 230...lots of C4s have made it many decades doing that. But no reason to chance it in my mind when we're not trying to hit microscopically better emissions numbers like GM was.
FWIW its probably also fine to let it hit 230...lots of C4s have made it many decades doing that. But no reason to chance it in my mind when we're not trying to hit microscopically better emissions numbers like GM was.
Thank you
Hawkeye56
Le Mans Master
Joined: Aug 2017
Posts: 6,942
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From: New Jersey
I can't comment on the later fans, but for the early cars dewitts actually lists the CFM improvement you'll get when installing it. My testing agrees with their numbers installed on their big (dual core I believe) radiator. However I suspect on the later ones the improvement isn't as great. Not that SPAL is a bad company... but it's hard to beat the R&D and reliability of an OEM fan. Just saying.
And as for temps, the fans on my 84 didn't come on until 238 degrees or so. I was out in 105 degree temps high humidity and A/C on max and stayed right around 200F with all the modifications I made to the cooling system. The later cars are just much better out of the box anyway.
And as for temps, the fans on my 84 didn't come on until 238 degrees or so. I was out in 105 degree temps high humidity and A/C on max and stayed right around 200F with all the modifications I made to the cooling system. The later cars are just much better out of the box anyway.
Pro
Joined: Sep 2024
Posts: 526
Likes: 114
Knowing nothing about the Dewitt fan, I have had success using 90s Volvo fan controllers which are a two speed controller that just needs 12v to operate and it has two relays built into it. Then I snag a 90s Ford Taurus (or similar) two speed fan that flows 4,000 CFM factory. Trim the sucker to fit and you are golden. You can trigger it with a manual switch or you can trigger it with a BMW two speed thermo switch. I use the one that starts at 80c for low and 88c for high. https://www.therangerstation.com/tec...fan/#gsc.tab=0 is a great write up for those who are interested.
Thread Starter
Burning Brakes
Joined: Mar 2019
Posts: 843
Likes: 149
From: Iowa
I can't comment on the later fans, but for the early cars dewitts actually lists the CFM improvement you'll get when installing it. My testing agrees with their numbers installed on their big (dual core I believe) radiator. However I suspect on the later ones the improvement isn't as great. Not that SPAL is a bad company... but it's hard to beat the R&D and reliability of an OEM fan. Just saying.
And as for temps, the fans on my 84 didn't come on until 238 degrees or so. I was out in 105 degree temps high humidity and A/C on max and stayed right around 200F with all the modifications I made to the cooling system. The later cars are just much better out of the box anyway.
And as for temps, the fans on my 84 didn't come on until 238 degrees or so. I was out in 105 degree temps high humidity and A/C on max and stayed right around 200F with all the modifications I made to the cooling system. The later cars are just much better out of the box anyway.
Thank you
Hawkeye56
Thread Starter
Burning Brakes
Joined: Mar 2019
Posts: 843
Likes: 149
From: Iowa
Knowing nothing about the Dewitt fan, I have had success using 90s Volvo fan controllers which are a two speed controller that just needs 12v to operate and it has two relays built into it. Then I snag a 90s Ford Taurus (or similar) two speed fan that flows 4,000 CFM factory. Trim the sucker to fit and you are golden. You can trigger it with a manual switch or you can trigger it with a BMW two speed thermo switch. I use the one that starts at 80c for low and 88c for high. https://www.therangerstation.com/tec...fan/#gsc.tab=0 is a great write up for those who are interested.
Thank. You
Hawkeye56