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| Another raditor fan not working thread (Page 1/1) |
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dhardison
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NOV 12, 02:46 PM
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1985 GT 2.8l - The radiator fan will NOT come on when the engine reaches temp.
The fan DOES work with the A/C switch on and also when 'hotwired', so the fan itself and relay are good.
I've replaced the coolant fan switch (the sensor next to the t-stat housing with the one-wire connector), but it did not help.
The temp gauge works properly as well.
Thoughts on what I can check next?
Thanks,
Dan
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IMSA GT
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NOV 12, 03:48 PM
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Although I don't know too much about this, my understanding is that the fan will not turn on until the temp gets to 235. Are you letting it get to that temperature? [This message has been edited by IMSA GT (edited 11-12-2023).]
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dhardison
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NOV 12, 03:55 PM
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| quote | Originally posted by IMSA GT:
Although I don't know too much about this, my understanding is that the fan will not turn on until the temp gets to 235. Are you letting it get to that temperature?
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235 seems high, but I don't know the temp either. I let the engine get to 225, which was high enough for coolant to spew out of the coolant overflow tank (has a new cap).
EDIT**: After some more research, the switch kicks on the fan at 230. I never let it get that high, mainly due to the coolant spewing from the tank. Maybe it was overfilled, I dunno.
I'm going to ground the connector at the switch to make sure the wiring is good.[This message has been edited by dhardison (edited 11-12-2023).]
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Frenchrafe
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NOV 12, 04:34 PM
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Coolant coming out of the overflow?
Seems like you have a bad radiator cap.
Check the hoses when the engine is running and warm. Are the hoses fairly rigid? If not, you haven't the right pressure in the cooling system.
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"Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero
https://youtu.be/hUzOAeyWLfM
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theogre
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NOV 12, 05:34 PM
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| quote | Originally posted by Frenchrafe:
Coolant coming out of the overflow?
Seems like you have a bad radiator cap.
Check the hoses when the engine is running and warm. Are the hoses fairly rigid? If not, you haven't the right pressure in the cooling system. |
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nice call as said is "boil over" & dash gauge reads < 250°F... If true, yes something is wrong but can be more then rad cap problem.
Coolant mix is first to test w/ any "float" tester because below 50/50 mix will easily "boil over."
Example: Any that put premixed coolant after flushing will have weak coolant because system has a lot of trapped water.
watch https://www.youtube.com/watch?v=GW-iI9Vgx58 Note that old coolant may be Ok for boil/freeze but lost anti rust & other additives that any float types can't tell.
That even w/ 15-16psi non-vent rad cap...
See https://web.archive.org/web...erocave/coolfill.htm & rest of section------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
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Vintage-Nut
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NOV 13, 09:07 AM
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I believe the schematic will help and check the coolant temperature switch wiring
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Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles[This message has been edited by Vintage-Nut (edited 11-13-2023).]
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dhardison
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NOV 13, 04:05 PM
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Thanks to all for the replies/info. Here are some updates from my end.
- I grounded the radiator fan switch at the connector and the fan comes on, so the wiring is good.
- I tested the coolant and the freezing point shows well above a 50/50 coolant/water mixture
- I fired up the engine and let it come up to temp long enough for the high-temp idiot light to illuminate on the dash, but the fan never came on. It also did not puke anything out of the front tank, so I may have just had it overfilled. The coolant hoses were tight, so it's building/holding pressure.
At this point the only way to get the fan to kick on is to engage the A/C or hotwire it.
So, all the following is new (all from RockAuto):
Radiator fan switch
Radiator cap (engine)
Thermostat
I'll check the schematic and see what I can determine, but for whatever reason the radiator fan switch doesn't appear to be doing its job. Faulty (new) sensor possibly......[This message has been edited by dhardison (edited 11-13-2023).]
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Patrick
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NOV 13, 04:25 PM
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| quote | Originally posted by dhardison:
I'll check the schematic and see what I can determine, but for whatever reason the coolant sensor doesn't appear to be doing its job. Faulty (new) sensor possibly...
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I assume you're referring to the fan switch.
A lot of us use Rodney's 210° on and 200° off fan switch.
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dhardison
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NOV 13, 04:32 PM
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Yes, the radiator fan switch. I bought the following from RockAuto (https://www.rockauto.com/en/moreinfo.php?pk=929686&cc=1249040&pt=4312&jsn=5).
Thanks for the info on the Rodney Dickman switch. Sounds like it's worth a try.
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theogre
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NOV 13, 05:06 PM
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| quote | Originally posted by dhardison:
So, all the following is new (all from RockAuto):
Radiator fan switch
Radiator cap (engine)
Thermostat |
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You must check the Rad Cap is a Non-vented Cap. See Rad Cap in Cave.
Do Not trust RA or anyone else, including "Stant" parts since since Stant is Gone.
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