TBI 305 electric fan question

Hey guys,

I have a quick question about my 1991 Caprice wagon with the 305. I put a new aftermarket radiator in it today. This radiator had the provisions for the 94-96 LT1 electric fans on it. If I put the dual fans on it, would that be enough to cool the normal flow (vs the reverse) system of the 305? I was planning on wiring one to be on with the ignition and having a controller make one come on at 210 or so. What are opinions on this? Let me know.

Thanks,
Collin

Collin,

The LT1 style fans will work just fine, but you don't want either of the fans on all the time unless the A/C is on. Maybe have one come on at 200 or so, and have the other wired up to the A/C switch or a manual switch on the dash, use relays of course. Others will probably chime in here and give you some better ideas. Good luck.

Mike

200OZ wrote:

Collin,

The LT1 style fans will work just fine, but you don't want either of the fans on all the time unless the A/C is on. Maybe have one come on at 200 or so, and have the other wired up to the A/C switch or a manual switch on the dash, use relays of course. Others will probably chime in here and give you some better ideas. Good luck.

Mike

Mike,

Thanks for the response. I was just worried about the primary fan kicking on and off all the time shortening its life but I see your point, I don't want to overcool it. For the secondary, if I hooked it to the A/C circuit, would I just run a wire from the A/C switch to the signal terminal on my relay? Is a regular 30 amp 5 pin relay going to work? Thanks again for any help.

-Collin

Well I'm not sure how many followers I have on this thread, but I'm going to keep up with it. Progress started today. It's going to be piece meal since this is my 96 year old Grandmother's daily driver and I don't want to have it down for long. Here is the picture with the mechanical shroud.

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and with the electric fan support

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I am going to leave it this way for a day or so, and once I figure out how to control the fans I will go ahead and put them in. I have also kicked around the idea of leaving the mechanical fan with the electrics as there is plenty of clearance to do so. Haven't decided for sure yet. Let me know what you guys think.

Thanks,
Collin

Well, I am curious how you will control the fans...

I have an extra set of electric fans and thought about butting them on the OCC...so keep us updated

brokecello wrote:

Well, I am curious how you will control the fans...

I have an extra set of electric fans and thought about butting them on the OCC...so keep us updated

I have a tentative plan but I'm not sure how well it will play out in practice. I'm planning on getting a fan switch for an 80-85 (I believe were the years) Firebird that turns the fan on at 212*. That is what I was thinking for the primary. The secondary will come on with the A/C and I'm also going to add a manual override switch. I'm just not sure if getting up to 212* will be too warm for the one fan to bring it back down. Some of the progress should happen this weekend, I will post results.

Collin:

The way I did the diesel and for awhile the Caddy, was I found a 103 C (215 F) degree switch from I think a mid 90s Buick V6. Used three relays (40 amp Bosch) with two signalled by the temp switch. The other one I ran a signal wire off the AC compressor clutch to turn on the primary fan only.

The power side of the relays, I ran through individual 30 amp inline fuses directly to the power bus on the fender. Activation power from a switched source (key on) and activation ground through the switch for the first two relays and activation power from the compressor for the third.

This setup allows for the primary on AC, and both over 103 degrees. The 103 switch turns off at about 95 C (203 F).

Hope this helps

Bill

convert2diesel wrote:

Collin:

The way I did the diesel and for awhile the Caddy, was I found a 103 C (215 F) degree switch from I think a mid 90s Buick V6. Used three relays (40 amp Bosch) with two signalled by the temp switch. The other one I ran a signal wire off the AC compressor clutch to turn on the primary fan only.

The power side of the relays, I ran through individual 30 amp inline fuses directly to the power bus on the fender. Activation power from a switched source (key on) and activation ground through the switch for the first two relays and activation power from the compressor for the third.

This setup allows for the primary on AC, and both over 103 degrees. The 103 switch turns off at about 95 C (203 F).

Hope this helps

Bill

Bill that is a huge help. When it comes to wiring, I understand the basics, but I am still somewhat of a newbie at it. I really appreciate the almost fool(me)proof instructions. Thank you so much. I will update when I get it installed.
-Collin

A word to the wise...do not run a mechanical fan without a shroud on one of these cars...it overheats pretty fast on a 90* day. I've run other vehicles without the shrouds and they've been fine. It must be the distance between the radiator and fan on these that poses a problem, but oh boy it gets hot quick. I've accumulated almost all of the parts for the conversion, should have progress tomorrow or Sunday. Thanks again for the advice guys.
-Collin

Glad I could help.

Bill