How to MarkVIII your OBS on a budget..!

[saif najd]

OEM T-stat mandates a 195F rating, that's what is in all my horses. After some extensive research on fan switches, I have decided to try a SW500 made by Airtex/Wells and used in 80's/90's GM 2.8L engines. Gonna pick one up after work tonight and begin the mod, I will report results...

Mine is from Mercedes

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[zomeizter]

Oakdog, the advertised closing of the switch was 230+/-8 degrees and they did not lie!! I ran my truck for a few minutes at high idle and the needle went past the 210 mark, right when it hit the 230 mark the fan came on and stayed on only for about 10 seconds, maintaining the set temp very well, this is one bad *** efan!! Now, as for the 230 degrees running temp, I'm not so sure I'm comfortable with it. Ima do some more searching and find a switch at my local autoparts house that keeps the gauge needle at 210-215. I set up the circuit so that the CTS turns on the high speed on the fan, the low speed I control in the cab with a manual switch, which will probably only be used when I'm giving the iron horse some hell in the sand Besides running a bit on the high side temperature wise with the current CTS, I really like the way it all came together, thanks to all that contributed on this thread! Now that I'm happy doing this mod on my OOBS, it's time to do the mod on my OBS Yukon, holler...

 

[zomeizter]

So after I completed the efan setup on my 'nali, I'm wondering if it is necessary to use the original shroud to encase the efan. I did not do that at all, but I ensured the efan was as close to the radiator core as possible. It is currently working great, as soon as the efan comes on, it only takes a few seconds for the temperature to drop and the fan shuts off. I guess we'll find out once I put this baby on the road and hit some dirt.

 

[saif najd]

So after I completed the efan setup on my 'nali, I'm wondering if it is necessary to use the original shroud to encase the efan. I did not do that at all, but I ensured the efan was as close to the radiator core as possible. It is currently working great, as soon as the efan comes on, it only takes a few seconds for the temperature to drop and the fan shuts off. I guess we'll find out once I put this baby on the road and hit some dirt.

I didn't use it (actually I dont have it haha) I would suggest you isolate the uper side of the radiator so hot air dont be pulled back be the efan.

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---------- Post added at 05:29 AM ---------- Previous post was at 05:29 AM ----------

I didn't use it (actually I dont have it haha) I would suggest you isolate the uper side of the radiator so hot air dont be pulled back be the efan.

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It is the upper space between the bridge and radiator

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[zomeizter]

Ok, so I found some CTS's that will keep the temp at about 210F. If anyone is interested, the part numbers are (Wells/Airtex) SW510 which closes at 210+/-8F and SW555 which closes at 210F and opens at 205F. Efan setups are currently working great.

 

[saif najd]

Ok, so I found some CTS's that will keep the temp at about 210F. If anyone is interested, the part numbers are (Wells/Airtex) SW510 which closes at 210+/-8F and SW555 which closes at 210F and opens at 205F. Efan setups are currently working great.

Great

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