i recently bought a 89 gt with midly built 306. my question is the car runs hot sometimes on the highway or at higher rpms. it has new stock pump,radiator 180 thermastat and a stupid flexlite fan with with with no clutch on it. i think the fan is the problem being it has no clutch and its robbing hp
cooling problem
- Thread starter schiccc
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Well, not having a clutch isn't what the problem is. It probally has a Flexfan on it, which the fins straighten out at higher rpm's to reduce drag, I bet this is your problem.
schiccc said:
Only 10 posts, but you have the right idea no doubt. Go ahead and put the stocker on there (if you have it) and look for an electric one. There are many options out there, do a search on "electric" and only search titles of posts, youll find tons of info. Or start another thread, it's up to you. I have the Black Magic.
I doubt the problem is the flex fan. If anything it's drawing more air thru the radiator than the stock one would. The fact that it's running hotter at higher rpm's suggests the coolant may not be running thru the radiator fast enough to cool it down, a flow problem. What is the condition of the radiator. I've seen partially clogged radiators cause this problem many times. And just because the top fins of the radiator look good doesn't mean the one you can't see are. May also be a t-stat not opening all the way. 
Michael Yount
Mustang Master
He says radiator and t'stat are new (t'stats can be bad when new, not often though). Overheating at speed indicates that something's blocking airflow across the radiator. Does the car have any custom bodywork on the front end that may be interfering? It's probably not even possible to do it, but could the flex fan be mounted backwards? At low speeds/idle, it would likely blow enough air across to keep the car cool, but at speed, it would be fighting with natural air flow across the radiator. IN any event, the stock fan only goes on one way; I'd remount it with the clutch and see what happens.
cooling
everything is new in the cooling system i was told it was the fanPRO50SC said:
TrophyHead
15 Year Member
Michael Yount
Mustang Master
When fans of any type aren't working properly, they usually don't affect cooling at speed. They affect cooling at low speeds - because they're not pulling enough air across the radiator - at idle, in traffic, etc. If the fan were the problem, he'd be overheating at low speeds, and it would start to cool as he increased speed. That's why I wondered if it's possible to bolt the fan on backwards - so it's actually trying to push air from under the hood out the front of the car. If that were the case - then the fan could be causing the symptoms described.
Flex fans work pretty simply. As the speed of the fan increases with increasing engine speed, the blades flatten out causing them to move less air, so they turn with less resistance. In theory they move the air that's needed at low engine speeds, and at higher engine speeds, the car is moving through the air quickly enough that the fan isn't needed. If it's mounted properly, I'm not sure how a flex fan is gonna interfere with cooling at speed.
Flex fans work pretty simply. As the speed of the fan increases with increasing engine speed, the blades flatten out causing them to move less air, so they turn with less resistance. In theory they move the air that's needed at low engine speeds, and at higher engine speeds, the car is moving through the air quickly enough that the fan isn't needed. If it's mounted properly, I'm not sure how a flex fan is gonna interfere with cooling at speed.
65ShelbyClone
Founding Member
Make sure your lower radiator hose has an anti-collapse spring in it. If it isnt there(rotted or missing) then the suction from the water pump at higher speed can collapse the hose and block flow.
Michael Yount said:That's why I wondered if it's possible to bolt the fan on backwards - so it's actually trying to push air from under the hood out the front of the car. If that were the case - then the fan could be causing the symptoms described.QUOTE]
Michael, didnt the new Goldwings have that - it pushed the air forward at speeds under like 10 mph so the riders legs would not get burned, but then reversed (pulled) at speed....? that did not work too hot (NPI) for that application, as i recall. LOL.
oh, where is your whole sig?
back to the thread: in addition to all that was said, i would make sure the original chin spoiler deal is on there. that thing, i think, helps to pull air up to the radiator. otherwise, air cant hit the radiator (i know that on 4th gen camaros, if that chin spoiler is AWOL, the car seriously overheats). just thought i would toss that out there.......remember in the old days when cars had those grill things.
i know you said it overheats at higher RPM's, but what kind of speed are you talking? like 4K in first gear, or does it do this at 4K in 3rd gear? (i skimmed the thread- sorry if i missed that).
good luck.
Michael Yount
Mustang Master
I would think the chin spoiler would be more of a higher speed contributor - but it's worth looking at.
Hadn't heard that about the Goldwings. It would surprise me - Honda RARELY lets stuff like that get through testing. They're not perfect, but they are excellent. The Gold Wing channels the hot radiator air away from the driver anyway - unless they open the vents in the fairing intentionally (cold weather driving). Was it a recall/fix?
Hadn't heard that about the Goldwings. It would surprise me - Honda RARELY lets stuff like that get through testing. They're not perfect, but they are excellent. The Gold Wing channels the hot radiator air away from the driver anyway - unless they open the vents in the fairing intentionally (cold weather driving). Was it a recall/fix?
Michael:Michael Yount said:
chin spoiler: i agree about it being an issue at higher speeds (say 25 MPH or more) - but i was not sure about what speeds he was having trouble at (part about me asking if this happened at 3 or 4K in 1st gear or same rpm in 3rd gear).
the Goldwings: it was a big deal and got a lot of press in some of the less commercial rags - you know the thin expensive one im talkin about (remember the GTX vs motorcycle oil study from way back)...that one.
here is a link with more techie stuff that you will get (that im sure i miss - and i dont want to get it wrong
:http://www.wingtechtips.com/overheat.htm
a lot of folks complained; probably also due to the excellence that GW owners expect.
