Thermostat Change

[Dean Fletcher]

I have suspected for a while the old thermo needs changed. The engine gets up to temp then fluctuates between 90 and 80 but if I give it some beans it goes up as expected. Today I drove to kendal had a slight glance at the temp and within a second it dropped to 20 then went straight back up to 87. The return journey there was no issues. So... I guessing the thermostat is a bit sticky and needs replacing as far as I'm aware it's never been changed in 11 years. .
Has anyone came across any decent thermostat Change DIY vids?

 

[Mr Greedy]

Even with a faulty thermostat, I wouldn't expect 70 degree temperature fluctuations within a second.

You might have a temperature sensor issue.
If might be air locks in the system (can cause rapid temperature fluctuations as the air moves round the system).
You might have a thermostat AND a temperature sensor issue.

"The engine gets up to temp then fluctuates between 90 and 80 but if I give it some beans it goes up as expected"
This bit sounds like thermostat.

 

[malcolm E53 AMG]

Usually throws a code up nowadays as the thermostat communicates with the ECU

 

[Dean Fletcher]

Usually throws a code up nowadays as the thermostat communicates with the ECU

No codes come up. The problem has persisted for well over a year now. No regen issues car runs fine just the temp goes up and down and little

 

[malcolm E53 AMG]

My S212 E350cdi thermostat lasted 6 years and 65k miles, there was no fluctuation in temperature just a steady decline to 60 degrees C over a couple of months before failing in the open position. If the car is fuelling ok you could live with it mine totally screwed up the fuel mixture to a cold engine choke setting so I had to get it done ASAP. At your car’s age/mileage though I’d do it in the near future MB‘s are renowned for short life faulty stats the one in my S210 lasted 50k miles - a very good earner for MB I’d say

 

[Dean Fletcher]

My S212 E350cdi thermostat lasted 6 years and 65k miles, there was no fluctuation in temperature just a steady decline to 60 degrees C over a couple of months before failing in the open position. If the car is fuelling ok you could live with it mine totally screwed up the fuel mixture to a cold engine choke setting so I had to get it done ASAP. At your car’s age/mileage though I’d do it in the near future MB‘s are renowned for short life faulty stats the one in my S210 lasted 50k miles - a very good earner for MB I’d say

Think ill just one ordered and get it fired on. My car bearly does 1000 miles a year now just used on a Saturday. Sits outside the house as I use the van for work related stuff and wife has her own motor. Love driving it tho nothing beats MB in my opinion.

 

[Dean Fletcher]

So today the old engine light came on with code relating to the catalyst temperature sensor bank 1 range/performance. This issue has been around for about 3 years now and pops up a couple of times a year then disappears for months. In fact there's a thread I posted on here back in 2018 about in. Am i right in thinking that the 2 issues cannot be related as one is the water temp and the other is the temperature of the cat.

 

[Blobcat]

So today the old engine light came on with code relating to the catalyst temperature sensor bank 1 range/performance. This issue has been around for about 3 years now and pops up a couple of times a year then disappears for months. In fact there's a thread I posted on here back in 2018 about in. Am i right in thinking that the 2 issues cannot be related as one is the water temp and the other is the temperature of the cat.

Your 2019 thread

 

[Dean Fletcher]

Your 2019 thread

Merci Mr B

 

[mioba]

Seems you need to get these niggles sorted for once and for all OP.
Lingering faults dont disappear , they stink after a while

 

[Dean Fletcher]

Seems you need to get these niggles sorted for once and for all OP.
Lingering faults dont disappear , they stink after a while

They don't stink very much when you literally sit in the car once a month

Seems you need to get these niggles sorted for once and for all OP.
Lingering faults dont disappear , they stink after a while