4200 Thermostat Replacement

[abyss]

My temp on the freeway is definitely around the 50 range as I expect it to be. With an ambient temp of around 22 and a constant 100 km/h between Melbourne and Torquay I would expect the airflow to keep the engine relatively cool. Maybe the GS behave in a different way?

Before I changed the stat on my GTA it was constantly at 50-75c and took ages to get up to 75c. Can never get up to 90c. Apparently the stat was stuck opened at all time. After replaced with a new stat the temp went back up to 85-90c. I was told the way to diagnose the stat is to see how long it takes to get up to the operating temp 90c. But this was for Alfa V6 only I suppose.

Back to the Maser, I was in a track day two weeks ago and the car water temp was consistently at 90c even the ambient temp was about 40c outside. I did 5 laps at each time to make sure I don't over push the car too much.

 

[conaero]

As its not that much ill get it changed. Any ideas how I bring the idle down? SD2/3?

 

[BennyD]

Most probably, but I don't know for sure.

 

[richard_masa_4200]

I just wanted to confirm that I can't read my temp gauge properly. When I say 50 I actually mean 75. So on the highway she hovers just above 75.

 

[CatmanV2]

They are wonderfully marked gauges, aren't they? I find the voltage particularly amusing, and as for trying to hit a speed in MPH at night....

C

 

[abyss]

I just wanted to confirm that I can't read my temp gauge properly. When I say 50 I actually mean 75. So on the highway she hovers just above 75.

Similar to mine as well. But still think it might be a good idea to replace mine in some stage.

 

[Tubber273]

Also Benny my idle revs are at 1000 rpm which I think causes the overheating when stationary.

What's your idle rpm Benny....or any of you other 4200 owners?

Interesting enough, I've had an issue with my 4200 cooling (see the thread "Cooling fans refuse to work") As I've watched the temp like a hawk, the normal operating/idle temperature is just under 195 (that would be 90C), and the engine idle has been a consistent 1000rpm. As my car has been into the dealership previously fr a misfire issue, I found out the standard idle is around 1000rpm. Hope this helps!

 

[Dean Kuan]

Im in borneo and my coolant temperature went up to 98c once in the traffic when the outside temp is 35c. I can hear the fan spinning and goes down slightly to 96 when start moving. never stays under 90 at all time. will get a thermostat replaced and hopefully can let it stays under 90.

A couple of weeks ago I had the misfortune to see my temp gauge creep past 90. Stay calm I thought, it's probably just the 30+ degree day in sunny Melbourne. As long as I keep moving we should be ok. Oh ****, traffic. Upwards the needle marched. I pulled over and waited for the traffic to disappear and then rushed back home.

So it would seem my thermostat had given up. Would this be an expensive trip to the indie, or could I do it myself? After a bit of research I figured I could do it myself.

I ordered a new thermostat from eBay in the US and it arrived about 10 days later. I also decided to go without coolant (it doesn't get near freezing in Melbourne) and are trying Redline Water Wetter with distilled water. I put the front end on stands and proceeded to get to work.

The thermostat is on RHS bottom of block at the front. It is easier to tackle from underneath. A few pointers.

1. Remove the bottom radiator hose from both ends as it gives better access to the thermostat.
2. Remove the top hose from the radiator, but leave it connected to the thermostat, it's easier to remove it as one piece.
3. When fitting the new thermostat attach the top radiator hose to the thermostat housing and fit as 1 unit.
4. Flush the radiator well before putting it all back together.
5. It would help if you had the hands of a Japanese schoolgirl. However, I have the hands of a rugby player and I still managed ok.

I filled her with the new water mix and let her get up to temperature. Yay, sitting just under 90. As it should.

I took her for a spin down the Great Ocean Road on the weekend and she is back to her normal cool self. Definitely a job you can tackle yourself if you are kindly mechanical.

Rich.

 

[mjheathcote]

Im in borneo and my coolant temperature went up to 98c once in the traffic when the outside temp is 35c. I can hear the fan spinning and goes down slightly to 96 when start moving. never stays under 90 at all time. will get a thermostat replaced and hopefully can let it stays under 90.

I'm not sure this is a problem with high ambient outside temperature.
I've a plug in obd2 'ultragauge' so see the coolant temperature digitally.
The cooling fans cut in around 95/96 if stuck in traffic and cut out early 90's, and when normal driving late 80's, 90 ish, but it isn't 35 degree C outside here!

Interestingly my BMW M140i with the B58 engine has a normal coolant temperature of 110 degrees!!

 

[Dean Kuan]

I'm not sure this is a problem with high ambient outside temperature.
I've a plug in obd2 'ultragauge' so see the coolant temperature digitally.
The cooling fans cut in around 95/96 if stuck in traffic and cut out early 90's, and when normal driving late 80's, 90 ish, but it isn't 35 degree C outside here!

Interestingly my BMW M140i with the B58 engine has a normal coolant temperature of 110 degrees!!

Hi Mate,

Thanks for your reply, this thread was dated back 9 years ago, still have your 4200?

Yea you are right. the fan cut in around 95/96. Also my car only comes with water. Perhaps replace with coolant first then see whats the result. but stays along 90 is solid cool, like Japanese car.

The BMW engine has high working temperature.

 

[TimR]

Have you thought about using a water wetter...?

 

[Dean Kuan]

Have you thought about using a water wetter...?

Hi man, lol yea actually i am doing some research now on how much to add in our cooling system. I am getting one tomorrow morning. Also i am not sure should i draw out some water or just direct add in the water wetter. Thanks man

 

[TimR]

Your car will dump what it doesnt want without consulting you at all...! So you risk wasting wetter if only a diluted concentration thereof...
I would probably siphon some coolant off and make room for the wetter...You can always top it off after.
There is a product that requires a complete and quite meticulous flush of the system, beffore a refill with the dedicated wetter...A different beast to the "add wetter" product. If you're flushing the system, which might be prudent if it worries you in the hotter climate...it is worth checking out in your search...?

 

[Dean Kuan]

Your car will dump what it doesnt want without consulting you at all...! So you risk wasting wetter if only a diluted concentration thereof...
I would probably siphon some coolant off and make room for the wetter...You can always top it off after.
There is a product that requires a complete and quite meticulous flush of the system, beffore a refill with the dedicated wetter...A different beast to the "add wetter" product. If you're flushing the system, which might be prudent if it worries you in the hotter climate...it is worth checking out in your search...?

Yea will check the ratio, I saw somewhere stated that wetter + water in a certain ratio has best result. Currently my car runs only water. No coolant. I getting a wetter tomorrow. Will update the process here.

 

[mjheathcote]

Hi Mate,

Thanks for your reply, this thread was dated back 9 years ago, still have your 4200?

Yea you are right. the fan cut in around 95/96. Also my car only comes with water. Perhaps replace with coolant first then see whats the result. but stays along 90 is solid cool, like Japanese car.

The BMW engine has high working temperature.

Yes I still have the car after 10 years.
Regarding just using water without coolant.
The coolant is not just for antifreeze, but for corrosion protection too.
You might not require any antifreeze where you live but you still require corrosion protection.
Check if using water wetter that it also adds corrosion protection too.

 

[Dean Kuan]

Yes I still have the car after 10 years.
Regarding just using water without coolant.
The coolant is not just for antifreeze, but for corrosion protection too.
You might not require any antifreeze where you live but you still require corrosion protection.
Check if using water wetter that it also adds corrosion protection too.

Alright. thanks mate. Glad that you kept it all along, such a great car, i enjoy every minute of driving it. have a few things to sort at the moment.
the rear driver brake light doesnt work, bulb is good. will be looking at the IGE.
the c1226 error with the abs ebd msp off lights, which is the abs pump.
And the driver side window only drop like few millimeter, i only get about two times normal and sometimes doesnt wanna drop when open door. gonna look into the drop switch
rear upper arm ball joint. replaced the dust cover and realise the ball joint alrd loosen.

despite all that the car is still brilliant.

yes the water wetter does comes with rust/corrosion protection. i pay more attention to the temperature while driving last night. the fan cut in on 95 then goes down to 90, driving at 27c the temperature is about 87-90. Yesterday was the first time it reached 99c in a slow moving traffic and 35c. the fan is screaming then i quickly find a path to let the car moves, then it start to go down 98-97-96. didnt get to move fast and constant, then i stop the car at 96c.

will see what the water wetter can do and update here

 

[Dean Kuan]

Alright. thanks mate. Glad that you kept it all along, such a great car, i enjoy every minute of driving it. have a few things to sort at the moment.
the rear driver brake light doesnt work, bulb is good. will be looking at the IGE.
the c1226 error with the abs ebd msp off lights, which is the abs pump.
And the driver side window only drop like few millimeter, i only get about two times normal and sometimes doesnt wanna drop when open door. gonna look into the drop switch
rear upper arm ball joint. replaced the dust cover and realise the ball joint alrd loosen.

despite all that the car is still brilliant.

yes the water wetter does comes with rust/corrosion protection. i pay more attention to the temperature while driving last night. the fan cut in on 95 then goes down to 90, driving at 27c the temperature is about 87-90. Yesterday was the first time it reached 99c in a slow moving traffic and 35c. the fan is screaming then i quickly find a path to let the car moves, then it start to go down 98-97-96. didnt get to move fast and constant, then i stop the car at 96c.

will see what the water wetter can do and update here

 

[Dean Kuan]

After I pour in the water wetter. The water get slightly milky, I suspect perhaps it started to actually clean up the whole system. It's not oily just milky. Will do a whole system garden hose flush soon. Thinking of Bypass the heater as well cos we will never need one in this tropical country.

I am wondering has anyone here change to a tropical thermostat like 82c and a lower temp fan switch on a tropical 4200 before? Thanks

 

[rusty iron]

My 4200 has always idled around 1150 rpm. Its mostly used in the country so it doesnt bother me much. Would prefer 950 rpm but doesnt seem to be adjustable. I have an X431 so if anybody knows how please let me know. The car is a manual by the way.

 

[philw696]

After I pour in the water wetter. The water get slightly milky, I suspect perhaps it started to actually clean up the whole system. It's not oily just milky. Will do a whole system garden hose flush soon. Thinking of Bypass the heater as well cos we will never need one in this tropical country.

I am wondering has anyone here change to a tropical thermostat like 82c and a lower temp fan switch on a tropical 4200 before? Thanks

That wants a really good flushing through my friend.
I'm thinking the radiator probably wants stripping and cleaning thoroughly and then your cooling will be fine.
Phil