over heating
Thread Starter
2nd Gear
Joined: Apr 2009
Posts: 2
Likes: 0
over heating
just had rad. flushed new therm. still overheating. the left fan comes on at 228d. off at 118 the one on the right doesn't come on at all. what shall i look for next? when i put the air cond. on both fans come on high speed. 95 roadster 350-300 .
thanks
dj
thanks
dj
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
Starting in 1995, with AC off, both fans should come on at slow speed starting at 228d F and if the temp keeps going up, at high speed at approx 236d F. Once the AC is turned on, both fans usually come on at high speed.
It's odd that only 1 fan comes on, but then both with AC on...
There should be 3 relays on driver side of the radiator shroud. 2 of the relays are identical, and one is different.
The relays work to select Slow speed by connecting the fans to power in series, and high speed by connecting them in parallel.
Perhaps one of the relays are not operating or have been replaced with the wrong relay. Considering how inexpensive they are, if you can't test them, consider replacing them, but be sure to get the correct ones and put them in the correct spot.
Thread Starter
2nd Gear
Joined: Apr 2009
Posts: 2
Likes: 0
over heating
went out and tried again and both fans came on at 228d off at 217d.
is is possable there is a bad relay. tried it later in the day and only the driver side fan came on at 228d. there is no crap around the rad.
djcorona
thanks
is is possable there is a bad relay. tried it later in the day and only the driver side fan came on at 228d. there is no crap around the rad.
djcorona
thanks
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
On my 96, the first fan comes on at 228, then the second at 230. Both come on with the A/C on. With a 180 t-stat my cruising temp is around 180 - 185. At a long light it will reach 228 but the one fan keeps below that, unless it's a hot day then it will hit 230 then cool down.
The LTx motors run hotter than you might be accustomed to. Don't worry, it's supposed to hit these temps (emission thing). If you are going above 230, then you have reason for concern.
The LTx motors run hotter than you might be accustomed to. Don't worry, it's supposed to hit these temps (emission thing). If you are going above 230, then you have reason for concern.
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Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
When/if the secondary fan does not come on, try nudging it to see if it starts (BE CAREFUL). If not, with the car off, try spinning it to see if its bearings are bad or making noise. Also, try disconnecting its connector and checking for corrosion -- wd40 works good to clean it.
Otherwise, it is likely one or more of the relays (2 same, 1 different). With the car off, try unplugging each and looking for any signs of corrosion on the plug/contacts and see if after reinstalling the problem goes away.
Otherwise, try first switching the 2 identical relays to see if anything works differently (i.e. no fans). If so, then replace the 'secondary' relay (after switching now primary). If not, then replacing the 1 different relay. BTW, if cost is not an issue, once you've id'd the bad relay, considering replacing the others nonetheless -- considering they likely have all reached their 'MTBF' (mean time between failure).
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
On my 96, the first fan comes on at 228, then the second at 230. Both come on with the A/C on. With a 180 t-stat my cruising temp is around 180 - 185. At a long light it will reach 228 but the one fan keeps below that, unless it's a hot day then it will hit 230 then cool down.
The LTx motors run hotter than you might be accustomed to. Don't worry, it's supposed to hit these temps (emission thing). If you are going above 230, then you have reason for concern.
The LTx motors run hotter than you might be accustomed to. Don't worry, it's supposed to hit these temps (emission thing). If you are going above 230, then you have reason for concern.
For the LT1s, starting in 1995, both fans always run together either in 'slow' speed (fans are powered in series) or 'fast' speed (fans are powered in parallel). This is accomplished via a difference in the fan wiring and the addition of a 3rd relay. Interestly, the fan motors are the same as pre-95s, where the fans only ran in 'fast' speed and where controlled independantly.
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
I presume your 96 is an LT4, which based on your above observations, apparently works differently than the 96 LT1s and I presume only has 2 fan relays mounted on the driver's side of the radiator housing..
For the LT1s, starting in 1995, both fans always run together either in 'slow' speed (fans are powered in series) or 'fast' speed (fans are powered in parallel). This is accomplished via a difference in the fan wiring and the addition of a 3rd relay. Interestly, the fan motors are the same as pre-95s, where the fans only ran in 'fast' speed and where controlled independantly.
For the LT1s, starting in 1995, both fans always run together either in 'slow' speed (fans are powered in series) or 'fast' speed (fans are powered in parallel). This is accomplished via a difference in the fan wiring and the addition of a 3rd relay. Interestly, the fan motors are the same as pre-95s, where the fans only ran in 'fast' speed and where controlled independantly.