Mark VIII Fan users, stop in...

[Mustang John]

I did the Mark VIII Fan install this weekend and have a question...

I used the Bosch 75 Amp relays as recommended in the instructions, and until I get the M22 sized temp sender tapped into the stat housing (somewhat painful ordeal) I'm running the fan whenever the car is running.

Seems that when I turn the car off after running awhile (hot) and turn it back on the the relay isn't turning back on unless I either tap it, or let the relay cool a few minutes... Seems like it may be taxing the relay and overheating it. Has anyone experienced this?


On a side note... Interesting thing is now with this install, the car runs MUCH cooler at idles with AC on. But actually runs hotter on the highway... It used to run about 215 with AC at idle on a hot 90 degree day and would start slowly climbing till it overheated or I started driving. The new fan fixed that!!!! (much happiness).

But, it used to run at around 190/195 on the highway, now it's running around 205 or a bit more... Weird huh? Guess the mech fan pulled more at speed than this MK VIII does... Hard to believe...

 

[onedownfiveup]

Yeah, I had a bunch of problems with a 30amp relay and my fan. I didn't have this fan but I have an O'Rileys special.

 

[Mustang John]

Aside from the relay thing...

Sadly, I'm dissapointed in the overall quality of this fan already... 170 bucks and it is still pretty bogus quality. The fan has a ton of play in the motor shaft/bearings, you can see the fan blade assembly flexing all over the place at speed from the play in the shaft.

Then when it all gets hot, you can actually watch the motor sit and slowly twist around from the centrifugal forces of the fan spinning slightly out of balance.

Jeez, I'm afraid to take this thing on a long trip at this point, it looks pretty unreliable to me. Maybe I expect too much, but I don't other electric fans on cars doing this...

 

[blown1989saleen]

Aside from the relay thing...

Sadly, I'm dissapointed in the overall quality of this fan already... 170 bucks and it is still pretty bogus quality. The fan has a ton of play in the motor shaft/bearings, you can see the fan blade assembly flexing all over the place at speed from the play in the shaft.

Then when it all gets hot, you can actually watch the motor sit and slowly twist around from the centrifugal forces of the fan spinning slightly out of balance.

Jeez, I'm afraid to take this thing on a long trip at this point, it looks pretty unreliable to me. Maybe I expect too much, but I don't other electric fans on cars doing this...

where did you get this fan? is it a factory original part? im using the exact fan from a salvage yard Mk8 with a bosch 75A relay and the fan keeps my 510RWHP daily driven blower car at 180-184 in bumper to bumper traffic and runs at 180 and below when cruising, im also using the VW temp sender too. sounds like you have other issues to me.


Scott

 

[Mustang John]

Yes, it's a OEM Ford Part from Houston Performance.

No other issues really other than I feel it is low in quality, But, I'm using an older 3 core that I'm going to replace shortly, that should improve cooling. But, the fan quality issue is sad.

(from another post of mine in another thread)
I made nice metal bracketry that holda all four corners extremely well. Considering other guys on the site used those fan mounting zippy tie things, I think my mounting is above par.

The actual outer shell is solid as a rock connected to the core support and the upper stainless steel radiator hold down. That part definitely isn't going anywhere.

What is flexing around is the motor when the support grid of plastic that it is attached to gets hot. There is a ton of play in the motor shaft and the blade wobbles slowly at speed, when it all gets hot, the motor twists and gyrates slowly. It's freaking me out.

Nothing to do with the way its mounted though. It's the low quality of the motor and its support cage... I'm truly PO'd that I wasted the dough on this thing, and now that it is trimmed up to fit the application, it's worthless as far as replacement from houston performance. I really have to see an OEM one that that is running in a MK VIII... Maybe they are just like this and live quite well?.

Interesting thing that my Junkyard owner friend said, is that he can't keep the MK VIII fans in stock. They're gone as soon as they come in for OEM replacement. Maybe I should have took that as a warning... Sigh....

I wonder if the new factory parts are just cheaper made than the original ones...

 

[D347643]

i got mine from houston perf and i love it. i have no idea what the deal is with yours but the only problem my fan gives me is it cools everything down too quickly. heh heh

Drew

 

[HISSIN50]

John, maybe send it back. sounds like you got an outta balance fan...? IIRC they used to have Siemens motors, which were problematic. i think the new ones are better..

that fan draws into the triple digits upon start up. im wondering if you are overloading the relay a bit (i think one wants to run a relay that is like 125-150% overboard)....that is my recollection from the smart electrical engineer types on threads. maybe that is why you need the tapping to jump it.....

at highways speed, the fan should not be doing anything (but impeding air flow). that is weird (kinda points to your rad, though it is the same one you had in there before, right?). weird.

for the controller, i know you have been busy at the shop lately and may not have seen this - Michael Yount really likes his fan controller - it is variable, so the motor is not just on full bore or off. neat idea (and easier on the charging system). pricey though. i think the site is
something like 'dccontroller', but i could be wrong (it is real close to that)..

congrats on the new fan - i would love to do one of those (we are over 100* already), but the gerbil on the treadmill under my hood could not take the amp draw.
i hope you get it fine tuned and it works as promised for ya!

 

[87'GTstang]

What did they sell you, a refurb or rebuilt fan??? The bad thing is that since you have already altered the fan, the question is if they will take it back or not.

 

[blown1989saleen]

the reason your friend cant keep the Mk8 fans in the yard ISNT because they are a bad part, its because they WORK, and people know this and they are buying them up. it seems to me you are the only one ive seen complaining of this problem which says it is an isolated incident. i replaced my first Mk8 fan after two years of use(it came from a salvaged Mk8 also)because i thought it burned up on me, turns out it was a bum circuit breaker, i replaced the circuit breaker and retested the fan and it still worked so dont question the quality of these fans at all, you can bet ford wouldnt have been using these in the Mk8's if they werent sure they were of quality


Scott

 

[Mustang John]

No, he actually never sells them to people that are doing this, and he was totally unaware of us doing these swaps. He mostly sells them to Lincon owners who have bad ones, or wrecked ones. Not like they get a ton of them anyways I suppose.

Yeah, I believe I saw the unit I have here has Seimens on it, made in Canada... Hmmm... It's brand new from the Houston Performance, 159 and shipping (nice guys there BTW)

Yeah, it seems to get out of balance, because the shaft has play in the bearing/bushings almost like they are worn out already and the assembly gets wiggy when the plastic gets hot and flexable... Since it is cut down, I doubt there is any warranty...

If the motor has play in the shaft, and the plastic get warms and start twisting around due to the "gyroscopic" force, I have to say, there is a quality problem here...

bleh...

As for the relay, I used the relay listed on sevral sites as "the" one to use, the Bosch 75 amp, relay from BPG... I think that the continuous duty thing here is a bit much for it... Although the fan is only supposed to draw 33 amps once it gets past the 130 amp startup... After running the fan awhile till it's all hot, it will not cycle until I let it cool a few minutes, or tap it, then it will click right on. I used 10 gauge wire for the power and 14 gauge to control the relay, so that seems ok...

Just a bad luck mod for this time around... Maybe I'll source a used fan and try it... I was just trying to do it right and get a new one... Go figure... haha...

 

[HISSIN50]

John, sounds like you got it covered as well as you can. if relays are not too pricey, you could try running two in parallel for fun, i suppose.

but i feel for ya. one would figure 'do it once and do it right' and be done with it, but that is not really the case. sorry to hear that.

 

[Michael Yount]

"But, I'm using an older 3 core"

John - I'm guessing the rad. may the reason for the heat up during cruise. At any speed above 30 or so mph, there should be enough air passing through the radiator that no fan at all is needed for cooling -- unless of course the radiator itself is 'tired'.

I use this to control my electric - www.dccontrol.com. There's nothing out there that's even close. It really rocks. And I spent more than it cost on relays and switches/wiring trying to get my set up working the way I wanted it to. Would have been less expensive to just buy the variable controller in the first place. I've seen numbers of more like 43-50A on the MKVIII at full tilt.

 

[Mustang John]

Yes Michael, I saw 9and envied) the controller you were using and had 'thought" it was maybe overkill, and these 75 amp bosch units seemed up to the task. I'm starting to wonder about getting it at this point.

As soon as the relays sit for a few minutes (or I tap them), they start working as usual, but that seems odd to me, and I wonder if it will kill them. Sadly, they are the relays that everyone recommends... 75 amps seems adequate for a 50 draw...

I agree about the radiator... I'll be getting a 3 row aluminum as soon as I sort this out, and I know that the fan isn't going to self destruct and eat the radiator. I think I may have just got a bum fan...

Funny thing that the mechanical fan cooled better at highway. I'm sure there is a physical reason such as the electric fan probably blocks air at some point of speed... The cooling it give at idle is truly awesome though.


Question to owners of the fan:
I have noticed that with the fan off the car, there appears to be a lot of play (left right not in and out) in the shaft bushing/bearing allowing the blade to move around a lot. Is this just how they are?

 

[blk92stangg]

I would think, regardless of if you modified it or not, a defective motor is defective. If you had modified the motor itself then I could see someone not honoring the warranty, but in your case... Could you just remove the motor from the housing and just send that back? In any event, I would not give up so quickly on contacting Houston performance. I am sure you could get some relief. Give them a call and see what they say. For 170.00 bones there is not much I would not try to get the issue resolved.

 

[gt90stang]

Mine has a little in and out play, but no side to side or up to down play at all. Is it possible that yours has shipping damage to the motor attach to the plastic frame? I think it is just preened into place with a few tabs around the motor mounting it to the frame. On mine the fan blade is about 3/8" from the radiator and no wobble at all running or not.

Good Luck, Don

 

[Mustang John]

Mine is more than 3/8 away and still contacts the radiator a bit. Particularly once the plastic frame is hot and the off balance fan blades start causing the motor supporting structure to start twisting the assembly around, or I make a decellerating turn.

Seems that the whole blade and shaft is moving inside the motor bushing. Weird that it doesn't make any bearing noise at all, and spins down quite freely. It just seems that the tolerances on this one are really loose.

I really love the amount of air it moves, but, it is giving me an uneasy feeling of imminent failure, that I've just been driving the Yukon lately and foregoing the stang...

Although it receives high praises, I have to say, the unit I have seems cheaply constructed and I feel it will fail eventually... I'm not satisfied at all other than the large amount of air it moves and the ability to cool the car extremely well.

Thank you for your replies!

 

[Sgt.5point0]

Electric fans aren't meant to run constantly, especially a hog like the mk8 fan. They're meant for "on-demand" use. I'd say wire in a rocker switch until you can get a temp. control, save that relay from burning up.

I had a hokey temp. control from Jegs, goofy piece but it worked and it was cheap.

I have my Mk8 strictly on switch control now, it always liked to turn on when I was staging so I had to ditch the temp. control.

 

[Stang951]

I think Sgt. hit it on the head for part of your problem. First you may have an off-balance fan. Call Houston Motorsports and see what they will do to help you out on that. Second if you are running an electric fan for a long period, you are heating everything up (motor, blade and mount) more than they are deisnged to take, hence the flex. Mine does not flex at all, but it only runs for a couple minutes at a time.
The reason you probably have a higher temp at highway speed is that the fan blade on the MarkVIII fan is blocking some of the airflow through the radiator and around the motor. Like Mike said at or above 30mph the fan doesnt really do a whole lot.