I didn't like how my car would get warm while sitting still with the A/C blowing. I noticed it would cool down once I was moving and came to the conclusion that the factory dual fan setup sucks, and I don't mean air,,,lol. They kind of hang out in the breeze with no shrouding to help.
I noticed on my wifes 97 Z-28 you can run the A/C without any fear of the engine getting warm and after looking I found that GM really improved on the design with a nice shroud to enclose the fans. I decided thats what I needed to do.

I found a pair of dual fan setups, one for an LS-1 and the other for an LT-1 so I bought them both. The shrouds differ slightly but nothing that would cause fitment problems. It is more of a cosmetic difference. I liked the looks of the LS-1 fan better so I started with that.

I went to GM and picked up a new upper radiator support and also some new belt routing and caution fan stickers. Thank god it was all still available. I did not want to modify my original pieces.

After removing the factory fans the LS-1 assembly literally fell right in like it was made for it. I did trim the side tabs off of the shroud since they are not needed on the 3rd gen and I also thought it looked much cleaner without them. Once in there I trimmed the new upper radiator support basically in a straight line to fit flush with the upper fan shroud, and the upper tabs worked perfect for holding the shroud in place, almost as if GM wanted this swap to happen,,,lol. I installed the new stickers and it looks like the car came factory with this setup. I am very pleased with the results.

When my car would idle before even without the A/C on, once the fans would come on it would basically hold that temperature, so the fans would not cycle, the motor would stay at 185 (when I have the fans coming on) and the fans would just continuously run at that point.
Now the fans come on and within 1-2 minutes it pulls the temp back down and the fans shut off as intended ( I have that set at 175). I had the A/C running while in the garage for about 10 minutes and the gauge never moved, the computer said the engine was holding 190 degrees. I couldn't be happier.

Anyone that is contemplating this swap I just want to say it was literally a breeze,,,lol. Even the factory harness plugged right in since GM has not changed the fan motors over the years. This may be old news but I thought I would share. Larry.

 

Do you have any pics? also do you have the stock Radiator?

 

I didn't bother to take pics but I can take some tomorrow if you like.
Yes it has the stock radiator still in the car. Been driving it for a week now and like the new fans. Also found out even though the motors are the same physically and will interchange they do have a different part number from the originals. So I looked up the specs to see what was really different between L-98 and LS-1 fan motors. The LS-1 motors are supposed to have more amperage so they should spin faster and pull more air.

They definately make more noise, when they come on it sounds like a vacuum cleaner. Sitting in traffic this week with the air on the temp gauge never reached the first mark, which is in the 185 range according to my computer. Nice improvement Larry.

 

If you could send me some pics i really would appreciate it. you can send them to BaddestZinNY@aol.com

 

I can do that tomorrow, no problem. Larry.

 

id be interested in pics as well.
always nice to see some fab work.
1slosbc@***.net

 

Good job...im in need of a new fan motor for my 90. Was thinking if the ls1 motor was physically the same. And spun faster pulling more air i might try and install the ls1 motor.

Does anyone know if the l98 fan will bolt up to the ls1 motor? Or if there is a upgrade?

Do you have any pics of your swap? I agree the fans need some type of shroud to pull the air.

 

The motors themselves are physically the same size and should drop right into the original fan assembly of a third gen. Even the weather pack connectors are identical and plug right in.
I can send pics if you shoot me an email, I have trouble getting them to post on here. Larry.

 

Do you think the L98 fan itself would bolt up as well to the LS1 motor? Thats good the wiring is the same. My local autozone doesnt have the motors in stock right now to compare them. If i have to swap the fan might as well do the whole thing like you did.

How much was the upper radiator support?

I might be doing the same swap as you sounds like its a worth while mod. And close to bolt it as well. A new motor is 45.00 so might be a good time to upgrade the whole system. I always wondered if the stock fans would pull more air with a shroud.

Thanks for the info, sent you an email.

 

I never tried but I believe the LS1 motor will bolt to the L98 fan assembly, as they are physically the same motor. Only difference I found in the GM books is the LS1 fan is rated a little higher amperage, spins a little faster so it pulls more CFM as a result. Plus the fact the LS1 fans are enclosed in a shroud it made sense to me to give it a try.
If a motor cost $45 I would probably just go with the entire LS1 fan setup with the shroud and drop that in.
I found mine complete for $60 out of a car that only had 40,000 miles on it. Measured some things and figured it would fit.
Picked up another upper shroud from GM for $25 bucks (or there abouts) because it requires trimming and I didn't want to trim the original. After that is was plug and play.
I will check my emails and shoot one back to ya. Hope you had a good New Year,,,,Larry.

 

oops double post..

 

Larry...i just picked up an LS1 shroud and fan assembly. Looks like a nice upgrade for driving in summer stop and go traffic with the ac.

I see from the pic you sent how you bolted the top in. But what about the bottum. I will figure it out when it comes i guess.

Heres a picture of larrys car with the fans. Hope you dont mind if i post it.
Its an awesome low mile IROC! And its for sale btw!


And a picture of the LS1 fan setup i bought.

 

I just sent you an email. Yes those are LS1 fans, and as you can see I dropped them right in. I only wish I could get a better angle at the car for better pictures.
Thats fine posting the pic, actually I should say thanks very much, thats really what this post needed, but I just don't know how
Anyway, you will love it with the A/C on in traffic.

If you look at the top of the LS1 shroud you will see how the tabs are offset. That is what I use the upper L98 plastic radiator support for, after trimming it will hold the LS1 fan shroud in place perfectly on those offset tabs.
Thats actually how they are held in place on the LS1 cars too. Larry.

 

Found these could this be an LT1 setup?

 

yeah thats the LT1 setup it has the upper and lower vent in the plastic. I put the LS1 fans in my car with the ls1 radiator. I figured it will be LS powered might as well have LS cooling. Don't have an engine to test temperatures but it does sound like a hurricane when they both turn on lol.

 

Yes those are LT1 fans, and they will drop in a 3rd gen as well. I have that setup as a spare for my 97 Z28 that I found when I picked up the LS1 fan assembly so I bought both. I installed the LS1 assembly though just because I like the looks of it better, the shroud is smooth and solid for the most part. Larry.

 

OK... the vents in the LT1, looks like they were still trying, to let some airflow thru. When the fans were off.

Looking at the part numbers for the fan motors. The LT1 has a couple different motors. One being the same as the L98 fans. So somewhere along the line they changed the motors. But like you mentioned..the connectors are the same from 85+ up.

The LS1 has a different motor/part number all together. Its slightly heaver, more windings maybe?

When i get the LS1 setup I will take pics and compare them for those interested. When the car is moving, it will cool right down. So it makes sence theres not enough airflow from the fans when sitting still. Not really a bigger raditator problem. But an airflow one.

My car never overheated with the factory fans. Even with the 406, But would get hotter, then i liked when taxed to the extreem. With higher compression, and advanced timing ,cooler temps make me feel alot better, when i step into it. Not to mention a bad tank of gas.

Replacing the fans seems a heck of alot easier and cheaper then replacing the radiator.

 

I was diging thru my pile of parts, and found an upper fan shround. Its for a single fan TBI car. looks like it might work, and i wont have to cut my dual fan radiator shround.

Did you use one, for a single fan larry? looks like it.

 

I just got a LT1 fan set for my z-28. Let me ask, what can I use for an upper mount? I have a clutch fan setup now and with building a 400 for this car I decided to get a dual fan setup to help keep it cool. I run a Griffin Aluminum radiator which is the universal type for chevy 31x19". Will there be a top unit I can use or am I on my own to fabricate something? Sorry, didn't mean to hijack this posting. Thanks for any help and suggestions..

 

you dont really need an upper mount, you can just use transmission cooler zip ties to hold it to the radiator.
works like a champ.
modified stock one will work, or a modified LT1 version, unless you got creative and fabricated one.

 

Sorry for the late reply.
MikeH,,,,Nope I used the dual fan upper shroud and carefully trimmed it to fit tight against the LS1 fan assembly. I just went to GM and picked up a new one to cut on,,,,didn't want to cut on the original one,,picked up the factory stickers as well to replace on the new cut shroud, so it all looks factory.
Didn't want to go the zip tie route, I really needed to go out of my way to make this look just like a factory install. Now people that view the car don't even realize it. Larry.

 

[QUOTE=firebirdjones;3192505]Sorry for the late reply.
MikeH,,,,Nope I used the dual fan upper shroud and carefully trimmed it to fit tight against the LS1 fan assembly. I just went to GM and picked up a new one to cut on,,,,didn't want to cut on the original one,,picked up the factory stickers as well to replace on the new cut shroud, so it all looks factory.

Hey larry...Got the LS1 fans installed. I did end up using the shroud for the single fan i had. And it worked great as well. I used a cut off wheel and a sawsall. Came out great, looks factory, if your not a thirdgen nut, you would never notice. I threw some new hoses on there too while i was at it.

Best part is even with the air going the car is running really cool now. Have to wait till summer and put it thru a stop and go traffic test. With the AC running to really see what it can do. But im pretty confident in the way its cooling now that it will work great.

The new fans and the tranny cooler should keep the trans from burning up as well in heavy traffic.

Thanks for making this post it helped me get my cooling system up to par with the rest of the setup.

 

Cool, glad to hear it. Larry.

 

Hey firebirdjones, which size are the two fans of the LS1?

 

Not sure exactly what part of the fan assembly you are asking about. The fans themselves are roughly the same size as the stock dual fans I pulled off. The big difference is the LS1 fans are encased in a shroud, and this shroud almost completely seals off the back of the radiator so the fans pull air through the entire radiator, which of course works more efficiently. The actual LS1 radiator is slightly smaller in width than a factory 3rd gen TPI radiator,,,(at least the ones I have measured are) so the LS1 shroud fits nicely with a slight amount of room to spare on the sides.
Does this help any? Larry.

 

I have been toying with this idea for my '83 Z28.I have already upgraded to the 3rd Gen dual fans from the factory HD clutch fan(the clutch failed and I got the whole fan setup for the price of a new clutch).And they do a very good job of cooling.On a side note I installed a LT1 dual fan assembly in my '95 Jimmy 4WD.It does a very good job in cooling and the interesting part is the radiator is the same size as my Z28's(and it has the oil cooler built in which may come into plans later).Firebird jones is correct the 3rd gen fan blades and the 4th gen are the same size in diameter and blade pitch.From what I've read all the fan motors used from the '83 HO single assembly up through '02 are the basically the same.There are a few variations mentioned in current draw and the length of the motor case.Personally I like the Siemens replacement motors(P/N PM517 $25-$35 depending where and come with a lifetime warranty)and have them on both fan setups.The LT1/LS1 fan assemblies have the retainer tab molded along the bottom as they fit the same in the 4th gen cars(and my Jimmy).If the fan case is wider than your radiator you want to seal both sides to make sure the all the air is drawn thru and not around the radiator.

 

Thanks for your explanation Larry, I was talking about the DIAMETER of each fan... The thing is that I live in Venezuela so It's kinda hard to find LS1 or LT1's fans because the last year the camaro was sold here was back in '95, so I found a Malibu 99 dual fan setup and installed it, It's been working great but i just want to compare with your work and see if i can improve mine or just contribute with the community

 

Oh I see. The fans themselves are the same size I believe. Although the LS1 motors are rated at different amperage than the old L98 TPI motors. They plug in and work the same,,,but the difference in fan speed is very noticable, the LS1 fans turn much faster.

Sounds like you found another alternative that works. Good info to know, and there may very well be something better out there than what I did. Larry.

 

I am going to have to do this for sure!! With the ProCharger and intercooler going in, I am going to do everything I can to keep it cool.

 

Yeah the blades are pretty much the same i compared the two. Its the shroud and motors that pull more air thru at low speeds.

 

Hi:

I am also in the process of installing a LSI fan in my '83 Z-28, you said you bought an upper radiator support from GM, can you please tell me what year of car I should order it from and why wouldn't I need the lower one to support the radiator as well?

Thanks,

 

I'm not sure what year('87 or '88)they started using dual fans but you can can find the upper mount in the classfieds on here,Modern Day Muscle( http://www.moderndaymuscle.com/inc/sdetail/774 ),Hawks or Ebay.The lower mount can be used to secure the fan shroud(http://www.moderndaymuscle.com/inc/sdetail/775 )but is not really neccessary as there is a lip the shroud will fit behind.The radiator itself sits in the support at the bottom with the top mount securing it.

 

so will a 4th gen radiator slide right into my 91 rs?

 

It would seem like it would but you'd have to check measuements and inlet/outlet locations(which I believe are the same).I installed a LT1 fan assembly in my '95 4WD Jimmy and her radiator looks to be the same size(I keep thinking to measure and keep forgetting to do it)and has a built in oil cooler.

 

Firebirdjones, are the fans 12" or what? Thanks, Jim

 

More pictures?

How deep are the LS1 fans? (top/center)

/N.

 

I believe the radiator hoses on the LS1's are in a different location. I'm not sure on the LT1's, but I'd verify that before ordering/buying one.

 

they are in different locations.
i used a stock ls1 upper, and i think a cavalier lower, though i cnt remember the year.

 

do you possibly have a pic of the radiator support after you cut it kinda as a guide to see how it needs to be cut i am doin the same mod to my 90 iroc

 

i used an LT1 upper radiator support.
cut off(CAREFULLY!!!) the angled lip on the backside, then cut it down about an inch to fit the form of the factory 3rd gen header support.
others have used the 3rd gen support and fans, but i upgraded to the ls1 units.

 

What year LS1 did those fans come out of? Just so I know what years to pick from. Thanks

 

any 98-02 year model z28/ss/trans am/ram air.
93-97lt1's have a very similar design, and actually fit the same radiator.
the shroud is about the only difference.
cosmetically, the ls1 shroud looks better.

 

Thanks stage20

 

Bringing back an old post here. Does anyone have any pictures of how/where to cut the dual fan upper mount to fit the LS fan shroud properly? I don't fancy using the zip-tie things going through the radiator.

 

Here are some pics of mine. The upper that I cut up was a single fan upper but Im sure you can get the general idea.

 

Those are some great pictures, thank you! did you have to modify the fan cage at all on the drivers side to account for the power steering box? I've heard that also had to be done.

 

The right side is the top of the fan on the driver side left side is the bottom. Just compare this shroud against yours and it should be obvious.

 

Wow, ok. Thank you very much for the close up, I really appreciate it.

 

I have a dual fan upper shroud and have started modding. Next is to see the fitment in the car but what are you using to hold the upper bracket to the fans? Is there any epoxy or is it simply pressure that holds it to the radiator?

Also, what holds it in the bottom? does it just sit down in the hole or is it bolted to anything?

 

I'm following along with your fan swap-it will be interesting to see how well your fans run using my 3-speed conversion fan harness. You wont have any issues amp/draw wise-that control harness is designed to support up to a 40A draw. Once you get it installed, check the fan positive at each speed and see what they draw.