TFSI Overheating. Fan won't start always.

Bebe

Guest
Thank you for the reply.

I've changed the big fan because i found out that the controle module is inside it... When the AC is running i think the fans aren't operating at full speed as i noticed... Is tere any other control modules?
Thanks
 

Lee M

Guest
Hi mate,

Not that I know of, I thought that there was only one controller.


Sent from my iPhone using Tapatalk
 

MJ afifi

Active Member
Mar 21, 2017
2
0
Hello guys!!
I have the same exact issue. Every single thing bebe said describes what iam experiencing except of the AC issue.
Thank God my AC works fine and I use it sometimes in a hot day to cool down the coolant fluid and engine block.

After 5 years from the issue, what was the cause. pease advise


I drive an mkv jetta 2.0tfsi 2008
 

MJ afifi

Active Member
Mar 21, 2017
2
0
Hello all

After 5 years of this thread, I would like to announce that I have the same exact issue bebe has.
Same thoughts came to me before even seeing this thread, I've done the same troubleshooting steps.
I've changed the G62, G83 and thermostats.
I've changed radiator and gearbox oil cooler as suspecting a clog in the system that might be expanding after getting hot.
Like you said bebe "It's obvious that something won't work after the engine heats up a few times"

I suspected the big fan and water pump as well. specially the water pump because the water flow in the return hose to the reservoir decreases after the engine reaches op. temp. or gets warm "not after a cold start".
BUT I am not going to change it because now I am at the point where my A/C died .. yes it is happening to me exactly.
Changing the water pump didn't solve the problem for you so, I assume it wont solve it for me.

I've bought Auto polar FIS last October to precisely monitor coolant and oil temperature readings on my cluster screen while I am driving. The auto polar FIS has 3 parameters for coolant however there is only 2 known coolant sensors all over the 2.0tfsi engines.
1 for the G62 called motor out temp, 1 for the G83 called coolant temp and the 3rd is unknown to me called Radiator temp. I contacted them recently to know more about the 3rd one.
Anyway I've found out that the 3rd parameter "Radiator temp" starts fluctuating like crazy after the engine been running for a while and the fans starts working after the reading of that parameter exceeds 77 or 80 degrees but no luck, that reading goes from 80 to 50 back to 70's then drops 60's in seconds then to 90's then drops to 60's maybe 50's. This is where the fans doesn't work properly. I think I might caught a thin thread that might be causing the whole issue.

You are the only one on the WEB who has the same exact issue as mine. I've been studying and searching for a year. No one understands no one has it no one knows except you and I.
 

Shane101

Active Member
Dec 27, 2018
1
0
Hi guys did u solve this in the end. I think i have the same problem. I have 09 cupra with only 13k on the clock and ive had the water pump, belt done 3k ago . It started a couple of weeks ago when i was going up multi storey car park and my coolant went upto 120 on the cluster as i parked up the car was running high idle aswell and then i turn it off the fans kicked in. I left the car as i went shopping. When i returned and drove the car the temps where normal 90 and didnt go above 93 intill i parked up and let the car idle for around 5mins and temp started to go upto 102 - 105 and the fans wearnt kicking in unless u turned the aircon on then it drops back down to 83. The car is fine when driving and only gose upto around 93 then comes back down to 83. I also have polarfis so have the the rad temp, motor temp and coolant temp on one screen and the coolant on the cluster aways stays at 90 even lo it reads 105 on polarfis screen. My rad temp also dose the same as Mj afifi. When the coolant is at 105 the rad temp is still at 78 and when you turn aircon on the fans come on and the rad temp go up and down. The problem is the fans won't come on unles the rad temp gose to high or you turn the aircon on even tho the coolant temp is rising to 105+ but all works fine when driving . It seams like a flow issue throw the rad on idle.
 
Nov 22, 2023
2
0
does anyone find the solution for this?
it was a faulty thermostat for me, check your water pump with the small hose at the coolant reservoir, pull it off if coolant comes out at idle and when reving it slightly it is working. check if you lower radioator hose is hot or the radiator itself
 
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