Engine Temperature Control

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Soltan

Active Member
Joined
Dec 3, 2007
Messages
276
Location
Birmingham
Car
E320 CDI Estate
Hi Folks
Been a while, but good to be back. Thought I'd post a story about my experiences at my last service and the benefits of a working thermostat.
I mentioned to my local mechanic that I'd noticed the car's temperature had gotten a little hot last time I was stuck in traffic on a hot day (this was last summer) and he naturally asked what temperature it got to. Almost 80 degrees I said and got a puzzled look in response. I told him that on the motorway it rarely goes above 40 degrees at which point the look changed from puzzled to disbelief. He asked how long it had been doing that, to which I replied since I'd bought the car in 2007.
He gently advised that there was likely to be a problem with the thermostat and to bring it in to get it changed.

When he took the old thermostat out he showed me a valve which is supposed to regulate the flow of coolant to keep the temperature regulated. It was stuck and would not budge at all.

Now that I have the new thermostat in the temperature rapidly goes up to around 90 degrees (a little alarming the first time I saw that :eek:) but then sticks there no matter if I'm cruising on the motorway or stuck in a traffic jam.

The upside is that my fuel economy has gone from low 20's for short journeys to around 31 mpg and from mid 30's to around 42mpg for motorways on average.

At this rate the fuel savings will pay for the new thermostat in just a few months.

So take from this tale what you will (I'm an idiot for not knowing the car was running too cold, that there was an obvious explanation for why my car was drinking like a fish, etc) but it just goes to show a friendly local indi can save you money as well as costing!

So my thanks to Mark for sorting that out for me. Hard to fix something if you don't even know it's broken in the first place.



As a followup to this I noticed about 6 weeks ago my mpg spiked dramatically, in fact I managed to hit 48mpg, unprecedented at a steady 65 mph on a trip down the M1. At first I thought it might be down to the change to summer fuel mix at my local Shell but then I remembered I'd dumped a whole bottle of Redex into the tank about a week before the journey and only topped up the tank since. In the last month or so the mpg has stared to come back down so that now on 50 mile motorway journeys on the M6 at a steady 65mph I get around 43-44mpg.
 
Hi Folks
Been a while, but good to be back. Thought I'd post a story about my experiences at my last service and the benefits of a working thermostat.
I mentioned to my local mechanic that I'd noticed the car's temperature had gotten a little hot last time I was stuck in traffic on a hot day (this was last summer) and he naturally asked what temperature it got to. Almost 80 degrees I said and got a puzzled look in response. I told him that on the motorway it rarely goes above 40 degrees at which point the look changed from puzzled to disbelief. He asked how long it had been doing that, to which I replied since I'd bought the car in 2007.
He gently advised that there was likely to be a problem with the thermostat and to bring it in to get it changed.

When he took the old thermostat out he showed me a valve which is supposed to regulate the flow of coolant to keep the temperature regulated. It was stuck and would not budge at all.

Now that I have the new thermostat in the temperature rapidly goes up to around 90 degrees (a little alarming the first time I saw that :eek:) but then sticks there no matter if I'm cruising on the motorway or stuck in a traffic jam.

The upside is that my fuel economy has gone from low 20's for short journeys to around 31 mpg and from mid 30's to around 42mpg for motorways on average.

At this rate the fuel savings will pay for the new thermostat in just a few months.

So take from this tale what you will (I'm an idiot for not knowing the car was running too cold, that there was an obvious explanation for why my car was drinking like a fish, etc) but it just goes to show a friendly local indi can save you money as well as costing!

So my thanks to Mark for sorting that out for me. Hard to fix something if you don't even know it's broken in the first place.



As a followup to this I noticed about 6 weeks ago my mpg spiked dramatically, in fact I managed to hit 48mpg, unprecedented at a steady 65 mph on a trip down the M1. At first I thought it might be down to the change to summer fuel mix at my local Shell but then I remembered I'd dumped a whole bottle of Redex into the tank about a week before the journey and only topped up the tank since. In the last month or so the mpg has stared to come back down so that now on 50 mile motorway journeys on the M6 at a steady 65mph I get around 43-44mpg.

lol i just saw the image of the mechanics face when you told him youd had it running for years at 40 degrees .er:doh:
and you are lucky you didnt knack something on the engine specially if you were doing motorway speeds,cold engine high speed they dont like
 
Yes indeed, quite agree.
As a followup as I was doing a long journey this weekend, I decided to see how much I could stretch the MPG to. Best I could manage was 49.8 on a long (steep) downhill stretch at just under 60mph.
 
Yes indeed, quite agree.
As a followup as I was doing a long journey this weekend, I decided to see how much I could stretch the MPG to. Best I could manage was 49.8 on a long (steep) downhill stretch at just under 60mph.


May shoot myself in the foot here but i am regularly getting 50+mpg on a 38mile run from cold but this is showing on the computer best so far is 57.8mpg but this is driving at around 50-52mph and use the lorry infront as a wind brake :crazy:
 
May shoot myself in the foot here but i am regularly getting 50+mpg on a 38mile run from cold but this is showing on the computer best so far is 57.8mpg but this is driving at around 50-52mph and use the lorry infront as a wind brake :crazy:

Tried the same thing myself last weekend. Most I could get was 49.8 and that was on a long steep downhil slope going at 55mph:crazy:
 
May shoot myself in the foot here but i am regularly getting 50+mpg on a 38mile run from cold but this is showing on the computer best so far is 57.8mpg but this is driving at around 50-52mph and use the lorry infront as a wind brake :crazy:

The fuel saving might be out of comparison if the lorry brakes suddenly and you dont notice!

Tony.
 

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