I recently replaced the coolant, thermostat, cap, hoses & gave everything a flush etc after having the radiator out fixing a leak in my ea.

ever since from a cold start the car reads really hot on the factory guage sometimes into the red before the thermostat opens and everything is fine again. after the first time it opens it works correctly.

i have an after market thermo guage in-line in the top hose (post thermostat) and the original temp sender in the normal position (pre thermostat) to keep an eye on whats happening.

strange thing is when the factory guage reads so hot and the thermostat finally opens the other guage still only goes up to around 100'c which is fairly normal i imagine.

using prestone yellow coolant mixed for 136' boiling point.

also have twin thermos one 16" one the engine side of the radiator and one 14" one the opposite side offset

Last edited by low_ryda on Sat Jun 07, 2008 2:33 pm, edited 1 time in total.

i would try a cooler thermostat..
std they start to open at 92 deg..
maybe try a 87deg thermostat?

i was thinking of doing that thanks troyman just wasn't sure what to look for. i was going to take it out for now but thought i might ask before i have to do the same thing twice.

might try the 82. also trident lists a 'high performance' thermostat for the falcs but no1 stocked one when i needed one so i haven't bothered since. would they be a different temp or maybe a different oriface size ?

I have been running a 82 degree tridon hi-flow Thermostat for about 3 years now, never had a problem. Still same fuel consumption around town and highway. BPT performance also sell the similar 82degree thermostat as a performance item("powerstat")

some generic thermostats come without the small hole cut in the plate that the original ford item has. This allows a small anount of flow through the thermo to allow it to read the temperature closer to whats actually in the block.
does urs have that hole?

yeah it had the hole, it was exactly the same as the old one i took out though the one i took out never fully closed. it opened when i tested it with the thermometer & water on the stove but it just never closed properly.

i just don't want to take the thermostat out n have it run too cold. there shouldn't be a reason to.

I wouldn't try a cooler thermostat, it's not the problem.

Looking at it simply, it looks like the thermostat is stuck at first. Maybe take it back and get another. You could try the kitchen testing method you mention, but then the scenario is different.

I don't think it should normally run at 100deg. Imagine what it would get to when the temp guage went from one-third to the red zone, 300deg? I've run cars with the cap only on the first turn and never noticed steam.

well the std thermostat starts to open at 92 deg and should be fully open at 100 deg..
and the 82 starts to open at 82 deg and is fully open at 90 deg..
its only a 10 deg difference and is noticable on the factory guage..
i had a similar issue.. with the 92 deg thermostat the temp guage would rise to atleast 3/4 on the guage before it would open..
and afer i put the 87 deg thermostat the temp omly rises to just under 1/2 before the thermostat opens..
but it could also be a problem wth the temp guage calibration..

you could always try a after market temp guage to get a accurate temp reading.

Okay.



Hmm, maybe the guages can get wacky like you say.

I do reckon you've got a problem beside the thermostat. Every car i've driven to my memory warmed up to the one-third mark and ran there firmly thereafter, unless there was something wrong. None of this going up the dial before the thermostat opens, or on hills, or when towing, or when the timing isn't quite right, etc.

Another thing though is the sheer volume of the system at around 15 litres, which is way more than any other vehicle i've owned to my knowledge. This could result in variations in cooling temp, for example, a lag effect. When the thermostat opens suddenly there is a big volume to pass through that could vary in temp significantly.

One might think a big volume helps, and maybe it does, but cooling in other vehicles i've owned has never been much of an issue, whereas in my falcons it's been an issue with every one of them. I wonder if there isn't enough reserve, meaning that whenever something isn't quite right it has a significant effect. I wonder if they deserve a more capable radiator.

im my case since i fitted the 87 deg thermostat the temp normally sits between 1/4 and 1/2 on the guage and i got the thermo fans set to come on between 1/2 and 3/4..
in summer on the hottest of hot days the temp sits around 1/2 and the fans only come on when sitting in traffic..now its winter the temp doesnt rise above 1/2 and the fans have no need to come on at all...

and its been running like this for almost 2 years now...

By my experience that's not right, as mentioned in my previous post. Decent cooling systems pretty much shrug-off the ambient temperature.

I've done everything to the cooling system on my XG, including a new viscous coupling, and it runs between 1/4 and 1/3, only rising slightly above 1/3 if i floor it, which might only be happenning due to advanced timing. Everything is stock apart from the EL long motor.

Even though this is good i still think it should be better, it shouldn't go up noticeably if i floor it, even though the timing is slightly advanced.

My EBII is exactly the same as the XG, 1/4 to 1/3, except the temp climbs beyond 1/3 as the load increases, i'm pretty sure the radiator is running at around 60%. In some circumstances i have to stop to prevent it from getting too hot.

yes but previously (past 30,000km's) there has never been a problem even with the d**k thermostat. thats wat i dont understand any other time i would agree with relaxed_diplomacy.

a guage would never read 300'c because the brass sensors will only create an accurate resistance within liquid, if you've ever cooked a car you would notice theres a brief period after it goes into the red it comes back down then goes bang.

i do have a custom dash fascia which required removing he needles but sub-sequent to that i had no problems.

also as i said after it's opened the first time theres no dramas, no heating problems whatsoever reguardless of ambient temp. traffic, heat waves & mornings so cold i have to wash the frost off my windows and still the only difference is how much better it performs the colder the ambient temp but no difference in block/head jacket temp (pre-thermostat)

& if it was physically that hot by the time the thermostat opened the post thermostat guage wouldn't spike up to just 100 - 120 & give a consistant reading. (normal operating temp is 90 - 120) depending on conditions but never out of the range once warmed up