Coupe out of character- temperature too LOW

[zainframe]

Guys,

Was driving along the highway today around 140/160km/h and suddenly my aircon jadi tarak sejuk - first though was 'here we go again - aircon problem lagi' but I noticed my water temp is way lower than normal - it's on the first notch of the gauge. Normally during high speed cruising especially at night the temp will get low but never this low. Then when I got home I left the car for 10mins with aircon on. Normally the temp will hit almost half and the second fan will kick in to lower it down but this time the temp never hit more than quarter at idle and the second fan didnt have a chance to kick-in. I dont think it's a fan relay issue- if it is than the temperature will shoot up to almost 3/4, it's just that the engine never hit the temperature that triggers the fan. I dunno whether this is related to the aircon issue or not.

Anybody experienced this before?

[raitag]

thermostat issue i think...

[hero]

Cylinder head gasket?

[enrick]

Thermostat...most definitely. Stuck open.

[wingwp]

Exactly same thing happen as mine but my thermostat was removed so not stuck & I can c water flowing into the tank, even lower the needle after I changed a new radiator & bigger fan

[bravosx]

thermostat issue i think...

Thermo jam open so constant flow of water that consistently cools the engine than is necessary...............me thinks

[stereotypical]

Looks like its thermostat stuck open..........

Taken frm FCCUK:-

Operating Temperature and Thermostat


Normal operating temperature, which should be reached about 5 miles or 15 minutes of driving, is between 83-86 degrees (slightly lower for a 16V) according to the ECU sensor on a car with a working thermostat. The dash gauge may read up to 10 degrees lower for cars with the dash sensor at the back of the block. Cars with the dash sensor in the thermostat housing may show a temperature closer to that of the ECU.

A car that takes ages to warm up or runs at 70 degrees has a failed thermostat. The thermostat on the coupe is a week point of the car. They last about 5-8 years at the most and fail in the open position. See further down for more symptom and how to do a quick check to see if it has or is failing.

The exact figures for the thermostat operation are:-

20v opening at 81°-85°
20v Turbo opening at 86°-90°
On both engines the thermostat will be fully open at 101°-105°

16v opening at 81°-85°
16v Turbo opening at 86°-90°
On both engines the thermostat will be fully open at 89°-93°

Part Numbers for thermostats:

20V Turbo Thermostat 46432157 at £42
20V NA Thermostat 46520785 at £38
Blanking plug required for the latest Fiat Themostats 7768914 at 36p
16V Turbo 7687205 at £45
16V 7772114 at £52

[stereotypical]

An easy way to check to see if a thermostat is failing:-

Start car from stone cold and open the bonnet
Feel the pipe that leads from the thermostat to the radiator.
If this gets warm in under 5 mins then the stat is stuck open (it's usual failure state).

[zainframe]

Thanks guys, I have a feeling it's thermostat also - could the aircon issue be related to it?

[zainframe]

Cylinder head gasket?

How could it be the gasket? care to elaborate?

thanks

[bravosx]

Cylinder head gasket?

Wouldn't that cause overheating?

[DeaDLocK]

Most likely is an open thermostat (common problem), but to my limited knowledge that doesn't explain the aircon issue. Might be some sensor somewhere that is bust and affecting the operation of the thermostat and aircon at the same time, or it could just be a double whammy.

Check and fix the thermostat as a first course. Until you do your car will probably run very rich and your fuel economy will be very bad.

[hero]

Cylinder head gasket?

How could it be the gasket? care to elaborate?

thanks

Combustion gases escape into the coolant, getting trapped at the thermostat area.
Just one possibility and definitely not the only.

[ognam]

Had this issue coming down Genting last Sunday. Temp went up one notch only. Even less than a quarter. As a result I didn't floor it. Went back to the normal 90 as soon as I hit KL. In my case, don't think it's thermostat

[Kelv27]

Ognam, I think yours was just a case of the engine taking abit longer to warm up with cool, wet weather and all coming downhill. When the car was in the UK, I did notice that it takes slightly longer to get up to temps during colder days.

[ognam]

Genting to gombak is a loonngg time. Haha.

[zainframe]

Friggin Italian machinery - usually people get into overheating issues, we get the opposite- enjin tak mau panas.

[Redd]

Had this issue coming down Genting last Sunday. Temp went up one notch only. Even less than a quarter. As a result I didn't floor it. Went back to the normal 90 as soon as I hit KL. In my case, don't think it's thermostat

happens all the time. when ur driving down genting ur seldom on hard throttle (more brakes than throttle) and the cool mountain air plus good airflow at speed keep your engine much cooler than usual. u shd see normal engine temps once u hit karak.

zain - ur a/c and stat issue could be related. possibility that ur fans are not turning on due to the coolant temp being low (stat stuck open), and thus ur a/c isn't cooling down as quickly. but afaik, the fans should come on as long as the a/c is on, regardless of coolant temp. check ur fan relays.

redd

[hero]

Had this issue coming down Genting last Sunday. Temp went up one notch only. Even less than a quarter. As a result I didn't floor it. Went back to the normal 90 as soon as I hit KL. In my case, don't think it's thermostat

happens all the time. when ur driving down genting ur seldom on hard throttle (more brakes than throttle) and the cool mountain air plus good airflow at speed keep your engine much cooler than usual. u shd see normal engine temps once u hit karak.

zain - ur a/c and stat issue could be related. possibility that ur fans are not turning on due to the coolant temp being low (stat stuck open), and thus ur a/c isn't cooling down as quickly. but afaik, the fans should come on as long as the a/c is on, regardless of coolant temp. check ur fan relays.

redd

Aircon fan(s) for Coupe work on OR logic.
Even if the engine not sufficiently hot for the fans to turn, the air-con will turn the fans on if the pressure in the air-con system rises ie temperature rises.

[zainframe]

Guys turned out to be a double whammy - thermostat koyak and some part in the compressor tercabut. Changed thermostat and screw-in balik the compressor.

[extercy]

all combine here are true. It goes something like this :
If AC is ON, slow speed of fan will turn ON.. for Coupe case since you guys got dual fan, 1 should turn On when compressor is On.. does not matter if it is cold weather or not...I think that is the Logic. This could cause your over cooling as your coolant thermostat is stuck Open.

Easy way to test coolant thermostat is by taking the car for a spin, then feel the hose from the coolant thermostat to radiator.. caution.. should be HOT to hold. If you can hold onto the hose for more than 10 seconds, then most likely, the coolant thermostat is stuck Open.

Both of your cases should not be related but it good that is is solved

wingwp.. It is better for you to install back the coolant thermostat since this will cause your FC to increase and lost of power due to slight over rich of the mixture and a dirtier engine.

[khlim7]

Hi

Currently experiencing the discussed problem with my 156 2.0 SS. Temperature will not go above 70 degrees, and even on mild traffic jam it only goes slightly above quarter mark. Tried procedure suggested by extercy and I can still hold the hose, so i guess it is the thermostat. Problem is I'm stuck outstation for a week or so, question is will it cause other damage if left it for now, other than increase in FC? Is there any temporary fix, DIY style?

[extercy]

Nope .. just hope it does not stuck close .. then you are screwed. It should just increase FC .. no damage I think.
Hope your problem solved by now

[nahar]

i had the stuck open thermostat, lasted about 1 years till one fine day and it stuck closed!

the hose blew up. radiator's water gone so as the water in the engine... and i m running on water cooling for about 20 mins before reached my house. Done top overhaul after that as the head gasket burnt.

[jamslau]

I had cold engine 60deg for ever on cold rainy days, hot days, temp 70-80 after changing thermostat RM250, now engine warms up to 80 within 5-10 mins on hot or cold days. That's the way it was designed to be.