Temp problem - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

SilverEA · 07-25-2003, 16:47

G'day all,

I have finally finished the rebuild of the old 3.9. Long problem filled process it was! But anyway, now I have a few problems left to sort out. My main ones are the transmission not shifting correctly, and the temperature not staying stable.
Lets start with the temperature. I will be driving along and the temp guage shows the temp just on the bottom of the normal operation box, which is where it used to sit. Then, as I keep driving along, the temp seems to rise in about 15 seconds to just above halfway, then drop again to just below the box in about 10 seconds, then it will start all over again. The thermostat was brand new. I replaced it again this morning thinking it was faulty, but it still does the same thing. I have bled all air out a few times, but there never seems to be any.

Next is my transmission. I have got it a bit overful i think, but that hasn't caused it to play up before. I have been just gradually putting my foot down (as I have replaced rings), and it changes at about 2200RPM, which means round town at 50-60 kays i am driving round in 2nd. It never used to have this problem either!

I am running out of ideas, so any help on either question would be appreciated...

6pAc|30nG|00n · 07-25-2003, 17:39

for the temp problem remove the thermostat and drill a small hole no more than 3 or 4 mm in the edge of it replace and bingo erratic gauge fixed (also make your head last longer)

As for the transmission im not sure, does it change to 3rd, or later if applicable, if you take your foot totally off the gas or does it stick in 2nd.

SilverEA · 07-25-2003, 19:01

it does change to third at about 70, but is stuck in 2nd when i slow from 60 ish

gregaust · 07-26-2003, 01:48

For the transmission if it's a 3 speed,check the kickdown cable is adjusted correctly..

SilverEA · 07-27-2003, 15:37

i think it is adjusted correctly. How are you meant to adjust it properly?

xdc351 · 07-27-2003, 21:50

Sounds like the temp sender is a bit sensitive, what temp thermostat are you running? Did you replace the water pump during the rebuild?

They can have problems with the seals hardening when left in the open for a while, I know mine had to be replaced after a long rebuild because it was leaking from the shaft seals.

As far as I can remember the kickdown cable should be fairly slack at closed throttle and become tentioned about 3/4 throttle, any tighter than that and it will hold gear too much and will destroy your tranny very quickly. 2nd gear in those things was not built to handle cruising!

If in doubt have it serviced by a professional.

SilverEA · 07-27-2003, 22:01

The thermostat temperature is 91 degrees celsius. The water pump wasn't replaced, but its not leaking. I have replaced the temp sender.... no difference. Re install my original thermo and the temp stays at one level, although it's cold. The original one has a hole with a valve in it. I dunno if they are meant to, but the 2 new ones i have tried havn't had 'em....

xdc351 · 07-27-2003, 23:58

Quote:

Originally Posted by SilverEA

The thermostat temperature is 91 degrees celsius. The water pump wasn't replaced, but its not leaking. I have replaced the temp sender.... no difference. Re install my original thermo and the temp stays at one level, although it's cold. The original one has a hole with a valve in it. I dunno if they are meant to, but the 2 new ones i have tried havn't had 'em....

Sounds like you have a very efficient radiator and a thermostat that is too hot. To get it a bit more consistent try running a 180F (82C) degree thermostat. It won't stop it getting so cold when it opens but it will stop it getting so hot before it does.

Also, because it will open more often, it should hopefully decrease the amount of time the water spends in the radiator and bring the overall temp up a little bit.