Alfa Romeo Forums banner

1 - 20 of 38 Posts

·
Premium Member
Joined
·
1,978 Posts
Discussion Starter · #1 ·
Hi all, I've got a few questions and soliciting some advice.
I'd do some researching myself but with 2 days to the weekend, hoping to save some time and get some parts on order.

I was driving tonight, and my 87's cooling fan exploded, also taking out the fan shroud and rad that I replaced about 3 years ago.

Questions:

What is the consensus on ditching the mechanical fan and going with an electric fan?
If I was to convert to an electric fan, I'd want it auto operating and not interested in a manual switch. Possible?
With an electric fan, is the shroud still necessary?

I know with the mechanical fan, the rad and the fan blade needs to come out to change the water pump. With an electric fan, can the water pump be replaced without having to remove the rad and electric fan? Just want to consider future pump replacement in the decision to convert or stay with mechanical.

Thanks
 

·
Super Moderator
Joined
·
11,783 Posts
What is the consensus on ditching the mechanical fan and going with an electric fan?
Sure, go ahead

If I was to convert to an electric fan, I'd want it auto operating and not interested in a manual switch. Possible?
Yes, though to make it automatic, you'll need to put a hole in your radiator and solder in the bung that holds the heat sensor.

With an electric fan, is the shroud still necessary?
Not the stock shroud, no. Electric fans come with built-in shrouds. And most people mount e-fans in front of the radiator in "pusher" mode, rather than behind (where the stock shroud goes).

I know with the mechanical fan, the rad and the fan blade needs to come out to change the water pump. With an electric fan, can the water pump be replaced without having to remove the rad and electric fan? Just want to consider future pump replacement in the decision to convert or stay with mechanical
Maybe you could R&R a pump with the radiator in place and no fan. However, it would probably take longer and involve more cursing. What's the big deal with pulling the radiator? If you are removing the pump, you've got to drain the coolant and remove the lower hose anyways and after that, it's just two bolts and the easily accessible upper hose to get the radiator out of the way.
 

·
Super Moderator
Joined
·
12,310 Posts
One thing that few consider is that the nylon fans do age and get brittle. They are an item that requires periodic replacement but there are some cautions in the replacement. You must use the steel backing plate under the bolts, and that plate should be flat. Do not over tighten the bolts or they will distort the backing plate, stress the nylon hub causing early failure. I use bow washers under the nut between bolt head and backing plate AND either a Permetex ultra grey or black on the bolt threads or Loctite Blue. Making the bolts very tight will cause early fan failure. The fan ages both with time and flex, so replacement after 10 years of use is reasonable.
All this makes electric fans attractive! The nylon fan uses engine power to move air even if it is not necessary. I like the later style Euro nylon fans with the tapered blades as they draw less engine power, but the cost here is more blade flex for a shorter life.
 

·
Registered
'84 Spider Veloce
Joined
·
569 Posts
Electric will also give a small HP gain, especially at hi RPM. If you have AC, you will need a puller (behind the radiator) installation. Stewart Jr. at APC recommended a Spal fan.

David OD
Laguna CA
 

·
Registered
Joined
·
450 Posts
I've had a pusher electric fan for 8 years no problems, quicker warm up and much less noise, alleged power gain but I didn't do it for that, cleaner engine bay, what's not to like, you can always keep a spare mechanical fan in the boot trunk just in case, easy to fit back on in an emergency
 

·
Registered
Joined
·
9,416 Posts
I was driving tonight, and my 87's cooling fan exploded, also taking out the fan shroud and rad that I replaced about 3 years ago.
there is always a reason for something suddenly failing, yes it might just be age-old plastic, but have you checked your engine mounts lately?
sagging mounts can allow the fan to contact the shroud.
 

·
Registered
Joined
·
2,085 Posts
You can use a fan control that has a probe you slip through the fins, such as the Hayden 3647 available in many places. I've used it on two Alfas and it worked well.
 

·
Premium Member
Joined
·
1,978 Posts
Discussion Starter · #8 ·
Thanks for the replies.

I was talking with Vintre last night, and he too brought up the possibility of engine mounts which I will look at tonight. I was giving it good on a curved highway on-ramp which would shift the engine to the driver side, so it seems possible the blade could have hit the shroud, but it was after I did explode after the car straightened out and pushed it to about 5500 rpm plus. The blade was always yellowish and on the car when I bought it 10 years ago. My bet and hope is on brittleness fatigue. Regrettably I didn't replace the blade when I put a new rad in a few years ago.

Of course electric fans come with their own shroud. Not sure what I was thinking.

I do like the idea of the temp probe vs having to weld in a bung.

I like the idea of power gain, but I suspect negligible.

All good info to consider. Thanks!
 

·
Registered
Joined
·
1,109 Posts
I've seen exploded fans dent the hood, ruin the radiator, shatter the shroud, slice through rad hoses, etc. Mounting an electric fan as a puller, is more efficient than as a pusher. Check the ends of the fan blades, have they been rubbing on the shroud? Follow Dom's advice and check the engine mounts, AND the transmission mount. My guess, they will need to be replaced too. Now would be a great time to do it. Drain and flush the block (coolant) too.
 

·
Premium Member
Joined
·
1,639 Posts
Well, depending on how much you want to change, the 1990 US spec S3 had two puller fans and a thermo switch to activate them. You could change to a 1990 radiator, add two fans and add a fan relay to your fuse box. This would require a different lower radiator hose also. There is a lot more room in front of the engine on a 1990 to access many things.
One of many things I like about the 1990 versus the earlier versions
 

·
Registered
Joined
·
9,416 Posts
as much as it sounds like a nice idea, I think changing to the 90> rad would be a nightmare.......the S4 rad is attached only by one point at the centre top and fits into 2 holes at the bottom
quite different to the S3 side mounted rad...so you'd have to do some welding/changing of metalwork.

And these days most aftermarket parts just cause trouble, nothing goes back like the original........even my 450 € (!) new S4 rad was not identical to the original...and it is only made for that car (well, and the S3.5), but they can't even get that fitment right anymore.

Stick to your old rad which can be recored at ye old fashioned shop:)....no plastic bits

Personally as to the PO question, If he never experienced any other trouble like overheating or the like, I'd personally just replace the original fan and shroud and start driving asap. That set up works for 99% of all S3s on the road quite efficiently.
:)
 

·
Premium Member
Joined
·
1,639 Posts
as much as it sounds like a nice idea, I think changing to the 90> rad would be a nightmare.......the S4 rad is attached only by one point at the centre top and fits into 2 holes at the bottom
quite different to the S3 side mounted rad...so you'd have to do some welding/changing of metalwork.

And these days most aftermarket parts just cause trouble, nothing goes back like the original........even my 450 € (!) new S4 rad was not identical to the original...and it is only made for that car (well, and the S3.5), but they can't even get that fitment right anymore.

Stick to your old rad which can be recored at ye old fashioned shop:)....no plastic bits

Personally as to the PO question, If he never experienced any other trouble like overheating or the like, I'd personally just replace the original fan and shroud and start driving asap. That set up works for 99% of all S3s on the road quite efficiently.
:)
I see your point. My 2 earlier S3s have the mechanical fan and the pusher fan in front of the radiator/condenser and they never overheat. Just love the accessibility of the later cars.
 

·
Registered
Joined
·
124 Posts
Hi all, I've got a few questions and soliciting some advice.
I'd do some researching myself but with 2 days to the weekend, hoping to save some time and get some parts on order.

I was driving tonight, and my 87's cooling fan exploded, also taking out the fan shroud and rad that I replaced about 3 years ago.

Questions:

What is the consensus on ditching the mechanical fan and going with an electric fan?
If I was to convert to an electric fan, I'd want it auto operating and not interested in a manual switch. Possible?
With an electric fan, is the shroud still necessary?

I know with the mechanical fan, the rad and the fan blade needs to come out to change the water pump. With an electric fan, can the water pump be replaced without having to remove the rad and electric fan? Just want to consider future pump replacement in the decision to convert or stay with mechanical.

Thanks
Mike, I converted my 69 GTV, 72 Berlina and 88 Spider to electric fans. I use the stock Alfa thermal switch that came out around 1990, a huge aftermarket fan, then did my own circuit with a stock Bosch relay and fuse. I had to play with the location of the thermal switch, but once I got that located correctly the fan comes on at about 175 and keeps the motor well cooled. I wired it hot so when I turn off the motor the fan stays on until the thermal switch turns it off. The big benefit is it extends the life of the water pump because the bearing stack on the impeller does not get hammered by the nylon fan that gradually becomes unbalanced as the heat drives out the plasticizers unevenly of the nylon.
1680636

1680637
 

·
Premium Member
Joined
·
1,978 Posts
Discussion Starter · #15 ·
Thanks for all the info.

I hate having my car out of commission any longer than necessary, and had this happened in the Fall, I would have figured out possible mods over the winter. I think SS4 has me figured out... do what you know works and get back out there!

I drove the car about 10 miles home with the broken (unbalanced) fan. Does this mean I should seriously be considering replacing the pump? Its not new, but also doesn't appear to be from 1987 either.

Thanks
 

·
Premium Member
Joined
·
1,639 Posts
Thanks for all the info.

I hate having my car out of commission any longer than necessary, and had this happened in the Fall, I would have figured out possible mods over the winter. I think SS4 has me figured out... do what you know works and get back out there!

I drove the car about 10 miles home with the broken (unbalanced) fan. Does this mean I should seriously be considering replacing the pump? Its not new, but also doesn't appear to be from 1987 either.

Thanks
I don't think the 10 miles hurt it much but since you do not know how old it is and the fact that you will be in there anyway, my advice is to replace it so you are not doing this again any time soon.
 
  • Like
Reactions: pennzo

·
Super Moderator
Joined
·
11,783 Posts
I hate having my car out of commission any longer than necessary, ... do what you know works and get back out there!
If you hate having your car off the road, then doing an e-fan conversion is not for you. It isn't a simple bolt-on task; you'll need to make brackets, do some custom wiring, etc. Sure, you can attach the e-fan to the radiator core with tie wraps, or those plastic thingies that come with the fans, but that's crude.

Just bolting on a replacement, stock fan will be the quickest and easiest solution. And it'll probably last another 10 years.

Agree that your water pump is fine after only 10 miles of spinning a broken fan.
 
  • Like
Reactions: John533i

·
Premium Member
Joined
·
1,375 Posts
I was in your shoes, but my fan was new, my shrowd was new, my motor mounts were less than 2yrs old. I hit an unseen dip in the road (sign wasn't kidding!) and lost ALL of the fan blades. They sheared at the hub. It took me a minute to figure out that there were no blades LOL. I had to turn off the engine to make sure that they weren't rotating. The car kept cool in traffic as long as I was moving, but would heat up at the lights. I made it home, though. I went electric after that. Mine is an 86. I just got another used radiator from a local Alfa nut, and it already had a bolt on the bottom driver's side that you remove to install a thermo switch for the fan. Yours will also probably, go look. You can find the switch at centerline fairly cheap. Then just wire in a relay; I got mine on Amazon. It comes on ~175 or so, and shuts off. I had to mount my fan engine bay side, as there was no room on my S3 to mount in front due to structural limitations. Most guys with S2's don't have to worry and can mount it there. I'll take photos if you like, but you can probably find some wiring diagrams on this site that other people have done. I kept the mounting hardware for the stock fan just in case. And the dimple in my hood from a flying fan blade; I kept that too.
 
1 - 20 of 38 Posts
Top