TBI Electric Fan Swap

Running them all the time falls into the "guy who thinks he is doing something good for his car, but isn't" category.

Well this thread is the primary reason I joined this website.

I got a 1993 Caprice LTZ and I put a Flex A Lite electric fan on it with a radiator temp probe. Well after a few years of this I think I found out I never did it exactly right. I think I heat cycled my engine and developed a bad head gasket and broken exhaust bolt due to hot spots in hot spot prone the 193 swirl heads. After reading a few threads that involved Fred Kiehl and his FW fans... I thought I would ask for some help.

What I realized too late is that the TBI ECM of course doesn't turn the electric fans on like the 94-96 LT1 cars did. I was foolish to think the temp probe Flex a Lite supplied would cool my cooling system down properly. What has happened is the up and down temp spikes have cost me numerous radiators, a head gasket, a broken manifold bolt and a lot of money. I think the fans I got are way too big and suck way too much CFM. I think the cars cooling system gets way to hot by the time the fans come on and then the fans cool things off too much way too fast. I kind of know this is the problem because the trans fluid is seeping past seals. This is in my opinion the case because as it cools too much it gets too thick and doesn't stay thin. Everyone knows trans fluid is designed to stay a consistent temp and stay thin.

So... after all is said and done... I thought I was doing something good for my car... but in the end.... this electric fan has nearly cost me an engine and a trans. The one thing the stock fan delivered was consistent temps on the oil, trans fluid and coolant. Once I took it off... I have basically ruined my car by depending on Flex A lite approach to radiator probe cooling.

I need help and advice on how to best proceed. I am going to put my stock fan back on... but I still really want an electric fan. I was hoping Fred or someone here could give me some advice on how to hook up the fans properly. I like the FW computer idea... sending in one of those ECM to get converted to EBL Flash sounds like a great idea. What I realized is that I don't have a trinary switch on the AC compressor or any relays at all. I have also been reading about how some guys turn one fan on and cycle the other one at the same time to keep the cooling system more consistent. This sound like a great plan. I have also seen water necks with NPT fittings in them. I think this would be a great place for a temp send unit.

Anyway guys... I seriously need some help here... if anyone might be able to provide some advice or a list of parts.. to get me going.. I would REALLY appreciate it a lot.

i think in your reasoning you are missing the function of the thermostat,.

I had this set up in a Chevy S10. And I'm planing on doing the same to my TBI.
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but instead of the Hayden 3647 I have this [You must be registered and logged in to see this link.]

When I did my swap over earlier this year, another problem I found was that the inlets/outlets of the passenger passenger side of the radiator tank did not match the old tank. It was relatively simple to to curl back most of those aluminum fingers all around the tank to take that palstic tank end off. The old one was exactly the same size. I did not need to swap the drivers side. I kept my old overflow tank and hoses that way.

YOu may find extra inlets/outlets for using the Tranny and oil cooler loops in the end tanks., it's easier to seal/ plug them off if unneeded

If you use one of those after market thermostat controls it's realatively easy to set when the come on.

Buy a cheap temperature lazer gun from Harbor freight, and grab a hair dryer. You can heat up the probe with the dryer, and use the gun to adjust the potentiometer on the thermostats control.

Personally i wonder if putting the probe into the radiator is the best way to take the engines temp. I'd suspect not. When you think about , you aren't really measuring the temp of the engine, just the coolant in the radiator. Gm put the coolant gauge in the stream of the coolant in the engine itself.
I just wonder if there's a better place for that type of probe to be strapped to that would be more accurate, like maybe on the water pump.

Just some idle thoughts,

Dave

So doing An electric fan setup on my 93 lo5, but what temp coolant switch should be used. I am setting mine up with a taurus dual stage single fan, pumps around 4500cfm when going, but I am not sure what temps I should have the low fan and high fan come on? Was looking at a switch that comes on at 198 for low and high at 221. I remember reading somewhere that these engines run good somewhere in the 200 range as the thermostat doesn't even open until 195.

So what would be the BEST temps for the low speed and then high speed to kick on?

Thank you!

lakeffect wrote:

Better yet. you can come for the weekend and get your knuckles dirty with me.

Here's a few other internet sources. Sometimes I find I get a better understanding or description from some authors than others. It all helps the cause in the long run. It all advances my knowledge.


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Dave,you may want to delete that top site since it is now a soft porn site for married swingers or something similiar.Wouldnt want to see you banning YOURSELF for a week!  

I have a set of FW fans.

I also still have everything to do this mod... I really should install those sometime. lol

Here is a site that has a three way temp sensor [You must be registered and logged in to see this link.]

So running a 195 thermostat, low fan on at 212 and high on at 230 and when ac is on? Napa switch ech-fs293 For 48 a piece, I would just have to build an inline adapter to mount it.

Hello everyone... I am sorry it took so long to get back here... I posted and forgot about it...

Juanjo_NY... thank you very much for that diagram. How much did your set up run?

Fred... that 3 way cooling approach is brilliant. Thank you so much.

Can you guys help me with a list of parts to get if I want to do this?

Anyway... I am really up in the air about what to do. Here's the thing... my Caprice's TBI 350 engine needs a lot of work and I kind of don't want to invest money in an old technology that has limited power potential. I am seriously starting to think a lot about a LQ4/4L80e swap instead of sticking with the old TBI system. That way I can have a modern EFI and have a PCM that has electric fan control built in but a lot more hp/TQ potential over the long run.

I've talked to a few people and they don't see any sense in spending money on rebuilding a 180hp 2 bolt main TBI Gen 1 engine with 180K on it and only getting 330hp through the TBI system when the LSx series 5.3/6.0 stuff starts out at 315hp/360hp stock. There will be a lot more money in setting up the car for the new school stuff but the LQ4 is a much better foundation for reaching my 400hp/500lb-ft. goals.

I agree if you have the budget. If you are doing it all yourself, you can probably get an engine for about $1200-1500, and a trans for about $300-500, wiring harness about $200. You need a really good set of fans, and a heavy duty radiator. The swap will require the adapter engine mounts, and a modified trans support, as well as a drive shaft. Shifter linkage may or may not work. You have a lot of little things to do too. Like moving the evap canister, and making sure all of the tanks and hoses fit. You should put duals on it and that will also require modding the trans support further. If you need cats, you have to find a place for them along with possible headers (stock LQ4 manifolds are a lot better than the LO5 units). You need heat shields for the driver's side of the exhaust. If you get someone to install it for you the total can run to $5000.

If you are going to upgrade the LQ4, here is some info: [You must be registered and logged in to see this link.]

Overall you have a lot more room to grow with an LQ4 or LQ9. The LQ9 requires premium gas. The LQ4 runs on regular.

You could also go with a big block, and build it. A big block will bolt right into the engine bay. You can get a 454 and have a ton of power, but you will have to get your trans built to take the punishment. A cast iron big block will weigh about 100 lbs. more than a small block.

Fred,you are right about everything except your 5 grand charge by a installer.With all the parts available for the swap being much cheaper now than a few years ago the swap can be done easily in 2 days by a pro for under 2 grand,with a warranty.Some shops do nothing but LS swaps which drives down the price too.

Is that if you bring your own engine and trans, or if they supply everything?

You bring your own engine and they use your old trans if its in good shape.LS engines have gone way down price wise,GM has made millions of them by now.

So uh... question (regarding original topic of this thread).

Would I be damaging anything by just wiring the fans to run when the key was on? I'm looking to finally do this mod this weekend when I do my doors and stuff.

Running the fans all of the time defeats the use of electric fans. It can also cause the coolant to run at too low of a temperature, and the thermostat may run almost closed. The idea of having an electric fan is to use it only when necessary to conserve fuel. Running the fans all of the time is not necessarily good for the fans either. They are not for constant use. It is relatively easy to install some type of sensor that works a pair of relays, and have one fan set up to override the input and run when the AC is on.

Hey Fred... thanks a lot for the link and all the fan info. For the record I have approached a few shops about the LSx install and you are about right... I had quotes of around $3K of labor if I supplied all the hard parts... and the figure I am trying to stay around is $2K-3K in hard parts. So yes... if a shop was involved it would be $5-6K roughly.

As far as the electric fan set up goes... never trust anything Flex a Lite has to offer as far as their VSC is concerned. The VSC turns the fan on and off and that is about all it does. It does not rely on a trinary switch... it only turns on/off when the A/C turns on/off nor does it have 2 speed fan settings and it doesn't allow cycling the fans. It has a temp probe at the inlet hose of the radiator. As my good friend Dave mentioned on the previous page... the temp probe SHOULD be located at the water neck area rather then the Radiator. Now when I bought my kit 5 years ago.. they didn't have a way of doing that. Now the VSC comes with a temp probe that can be mounted in a water neck... but it didn't when I bought mine 8 years ago.

I also warn against getting a fan that is too big. My fan pulled a lot of CFM and most likely it was way too much for it. I think this also lead to severe temp cycling of the cooling system. The key to the cooling system is not only to keep the temp low but also to keep the temp consistent. This is especially important when you have your engine fluids running through radiator mounted coolers. That is the one main thing about the belt driven clutch fan... it kept the temps across all though fluids steady. So when you guys are thing about doing this...take this into consideration. When I do this again... most likely I am going to get the 94-96 9C1 external coolers for the trans and oil. I think that is the safest arrangement with an electric fan.

Stingroo wrote:

So uh... question (regarding original topic of this thread).

Would I be damaging anything by just wiring the fans to run when the key was on? I'm looking to finally do this mod this weekend when I do my doors and stuff.

Check with Tom Wingo, he is installing a dual fan setup in his wagon.

Fred... do you think this is too much fan for the TBI engine?

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I do not know anything about the fan. A lot of people have used the LT1 fans, but you have to rig the screw/bolt for the plastic end caps on the radiator. The upper and lower clips are easy to put on the radiator, and you need some long screws for the top.

Fred Kiehl wrote:

I do not know anything about the fan. A lot of people have used the LT1 fans, but you have to rig the screw/bolt for the plastic end caps on the radiator. The upper and lower clips are easy to put on the radiator, and you need some long screws for the top.

I was just wondering if you thought the 4600cfm that this fan pulls is too much when compared to the stock 93 FW dual fan or the stock 94-96 LT1 fan.

JBLTZ wrote:

Fred... do you think this is too much fan for the TBI engine?

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Its a massive overkill for your wagon and only the primary fan will be used most of the time.Now if you are going to install a LS9 and start doing roadracing/top speed events its probably a good fan.  

I don't have a wagon. I have a sedan. I have this fan on my 350 TBI. I feel that I over-cooled my cooling system with this fan. That is what I am asking the question. Both fans run at once... they start out at 80% and then go down as the temp decreases.

For the record I intend on switching to an LSx engine in the future.

As long as your thermostat is functioning you cant be over cooling your cooling system,the fans just are not having to work very hard if at all.

I'm not always sure if my t stat is opening up because it takes so long from the fans to come on after start up. I am also wondering if my engine is getting too hot and then being cooled too much after they do finally come on.

OK... and while I agree with the coolant system portion... I am also questioning if the viscosity of the trans. fluid and engine oil was affected by using such a large fan.

What I am really after here is if the fan caused fluctuations in temp consistency due to the fan taking the temp reading for fan activation at the radiator nearest the top inlet rather then the cylinder head or water neck. As Dave B. pointed out above... the VSC rad. mounted temp probe is taking a reading of the engine coolant temp. external from the engine. Doesn't this mean the engine is getting hotter then if the car still had a belt driven fan?

This makes me think the engine gets hotter then its supposed to and the fans are turning on later then if they were controlled by a computer taking a reading at the water neck or cylinder head. These temp fluctuations are heat cycling all the fluids going through the radiator and that is causing temp fluctuations in the trans and engine as well. I believe this because my evidence is a problem with seeping transmissions seals... which have been replaced multiple times.... but ultimately I don't think the condition is due to bad seals... I think its due to the trans. fluid becoming too thick from to being cooled too much. After all... the belt driven fan would be more likely to keep the temps consistent across all fluids.