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Author Topic: Possible Thermostat Issue  (Read 5614 times)

Offline K1NGY14

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Possible Thermostat Issue
« on: July 31, 2016, 08:11:21 pm »
Hi all,

Sorry to create another thread about this.

Basically I'm having a little issue with my GTI is have a slight hesitation and it's like the car is over fueling under load. My car gets up to temperature well on the dash, it shows a solid 90 but when I check the temps on the a/c dials it doesn't go about 74-76.

Does that sound like my main thermostat has failed and may be causing a hesitation and MPG issue?


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Offline Pesky jones

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Re: Possible Thermostat Issue
« Reply #1 on: July 31, 2016, 08:57:23 pm »
I cant comment for the hesitation issue, but my guess for the car not getting up to the correct temperature would be the main thermostat. Does it not get there at all? If it was an inline thermostat at fault I expect it would get to 90 eventually, but not for a while. If it simply isn't getting to temp i'd say main stat. The gauge itself is usually eager, but eventually the real temperature does catch up with the gauge and both will sit around 90.

If your coolant is only 75 degrees then your engine isn't running how it was designed to run, and MPG will suffer because of it.
« Last Edit: July 31, 2016, 08:59:18 pm by Peskyjones »

Offline K1NGY14

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Re: Possible Thermostat Issue
« Reply #2 on: August 01, 2016, 04:34:40 pm »
I cant comment for the hesitation issue, but my guess for the car not getting up to the correct temperature would be the main thermostat. Does it not get there at all? If it was an inline thermostat at fault I expect it would get to 90 eventually, but not for a while. If it simply isn't getting to temp i'd say main stat. The gauge itself is usually eager, but eventually the real temperature does catch up with the gauge and both will sit around 90.

If your coolant is only 75 degrees then your engine isn't running how it was designed to run, and MPG will suffer because of it.

Thanks for this mate, I've got myself booked in at Awesome in a few weeks to get it changed.

Hopefully that'll sort the issue :)


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Offline Pesky jones

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Re: Possible Thermostat Issue
« Reply #3 on: August 01, 2016, 05:08:41 pm »
No worries pal glad I could help.

Offline The Red Warrior

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Re: Possible Thermostat Issue
« Reply #4 on: November 17, 2016, 09:25:57 am »
I cant comment for the hesitation issue, but my guess for the car not getting up to the correct temperature would be the main thermostat. Does it not get there at all? If it was an inline thermostat at fault I expect it would get to 90 eventually, but not for a while. If it simply isn't getting to temp i'd say main stat. The gauge itself is usually eager, but eventually the real temperature does catch up with the gauge and both will sit around 90.

If your coolant is only 75 degrees then your engine isn't running how it was designed to run, and MPG will suffer because of it.


Thanks for this mate, I've got myself booked in at Awesome in a few weeks to get it changed.

Hopefully that'll sort the issue :)

@K1NGY14 did you get this sorted out? ie was it indeed the main thermostat?


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Offline K1NGY14

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Re: Possible Thermostat Issue
« Reply #5 on: November 22, 2016, 05:18:40 pm »
I cant comment for the hesitation issue, but my guess for the car not getting up to the correct temperature would be the main thermostat. Does it not get there at all? If it was an inline thermostat at fault I expect it would get to 90 eventually, but not for a while. If it simply isn't getting to temp i'd say main stat. The gauge itself is usually eager, but eventually the real temperature does catch up with the gauge and both will sit around 90.

If your coolant is only 75 degrees then your engine isn't running how it was designed to run, and MPG will suffer because of it.


Thanks for this mate, I've got myself booked in at Awesome in a few weeks to get it changed.

Hopefully that'll sort the issue :)

@K1NGY14 did you get this sorted out? ie was it indeed the main thermostat?


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Yes it has sorted the issue and my car is now running fine and my MPG has returned back to normal.


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Offline The Red Warrior

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Re: Possible Thermostat Issue
« Reply #6 on: November 23, 2016, 08:16:53 am »
Good to hear.  :happy2:
Hopefully it will do the same for mine when the part arrives and I install it.

Offline numec

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Re: Possible Thermostat Issue
« Reply #7 on: January 19, 2017, 11:27:20 pm »
I cant comment for the hesitation issue, but my guess for the car not getting up to the correct temperature would be the main thermostat. Does it not get there at all? If it was an inline thermostat at fault I expect it would get to 90 eventually, but not for a while. If it simply isn't getting to temp i'd say main stat. The gauge itself is usually eager, but eventually the real temperature does catch up with the gauge and both will sit around 90.

If your coolant is only 75 degrees then your engine isn't running how it was designed to run, and MPG will suffer because of it.


Thanks for this mate, I've got myself booked in at Awesome in a few weeks to get it changed.

Hopefully that'll sort the issue :)

@K1NGY14 did you get this sorted out? ie was it indeed the main thermostat?


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Yes it has sorted the issue and my car is now running fine and my MPG has returned back to normal.


Sent from my iPad using Tapatalk

how much was it for the thermostat job?

Offline K1NGY14

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Re: Possible Thermostat Issue
« Reply #8 on: January 19, 2017, 11:28:35 pm »
I cant comment for the hesitation issue, but my guess for the car not getting up to the correct temperature would be the main thermostat. Does it not get there at all? If it was an inline thermostat at fault I expect it would get to 90 eventually, but not for a while. If it simply isn't getting to temp i'd say main stat. The gauge itself is usually eager, but eventually the real temperature does catch up with the gauge and both will sit around 90.

If your coolant is only 75 degrees then your engine isn't running how it was designed to run, and MPG will suffer because of it.


Thanks for this mate, I've got myself booked in at Awesome in a few weeks to get it changed.

Hopefully that'll sort the issue :)

@K1NGY14 did you get this sorted out? ie was it indeed the main thermostat?


Sent from my iPhone using Tapatalk


Yes it has sorted the issue and my car is now running fine and my MPG has returned back to normal.


Sent from my iPad using Tapatalk

how much was it for the thermostat job?

About £130



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Offline The Red Warrior

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Re: Possible Thermostat Issue
« Reply #9 on: January 20, 2017, 07:33:31 am »
Mine cost me 4 hours of labour  :signLOL:

Offline numec

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Re: Possible Thermostat Issue
« Reply #10 on: January 21, 2017, 04:35:22 pm »
I cant comment for the hesitation issue, but my guess for the car not getting up to the correct temperature would be the main thermostat. Does it not get there at all? If it was an inline thermostat at fault I expect it would get to 90 eventually, but not for a while. If it simply isn't getting to temp i'd say main stat. The gauge itself is usually eager, but eventually the real temperature does catch up with the gauge and both will sit around 90.

If your coolant is only 75 degrees then your engine isn't running how it was designed to run, and MPG will suffer because of it.


Thanks for this mate, I've got myself booked in at Awesome in a few weeks to get it changed.

Hopefully that'll sort the issue :)

@K1NGY14 did you get this sorted out? ie was it indeed the main thermostat?


Sent from my iPhone using Tapatalk


Yes it has sorted the issue and my car is now running fine and my MPG has returned back to normal.


Sent from my iPad using Tapatalk

how much was it for the thermostat job?

About £130



Sent from my iPhone using Tapatalk

That seems reasonable. is this just the main thermostat change?

Offline RobC

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Re: Possible Thermostat Issue
« Reply #11 on: June 22, 2017, 09:00:36 am »
Hi all,

Sorry to create another thread about this.

Basically I'm having a little issue with my GTI is have a slight hesitation and it's like the car is over fueling under load. My car gets up to temperature well on the dash, it shows a solid 90 but when I check the temps on the a/c dials it doesn't go about 74-76.

Does that sound like my main thermostat has failed and may be causing a hesitation and MPG issue?


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Apologies for digging up an old thread but my symptoms are very similar so didnt think it warranted a new one.

Similar to @K1NGY14 my dash gauge shows a solid 90° and doesnt take long to get there. However, Ive taken the car for a drive the last couple of nights and driven slow, hard/fast, on open roads and in traffic and the temp on the Air Con read out sits around 77-82°. Not once have I seen it creep above 82° and I know this is still hotter than @K1NGY14 was seeing but is its still too low? What figures do you guys see? Car is a stock ED30 by the way.

Cheers.

Offline The Red Warrior

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Re: Possible Thermostat Issue
« Reply #12 on: June 22, 2017, 09:46:35 am »
Probably main thermostat stuffed then. Mine used to be slow to get up to temperature on the dash, (about 20 minutes of rush hour commute) and then after changing coolant it wouldn't show above 80°C on the dash, unless I sat in stopped traffic for a few minutes when it would creep towards 90°C and then drop again as soon as I started moving.
All good after putting in a new main thermostat. Up to 90°C on the dash in about 7 minutes now.

Do you plan on changing it yourself?

Offline RobC

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Re: Possible Thermostat Issue
« Reply #13 on: June 22, 2017, 11:34:22 am »
Probably main thermostat stuffed then. Mine used to be slow to get up to temperature on the dash, (about 20 minutes of rush hour commute) and then after changing coolant it wouldn't show above 80°C on the dash, unless I sat in stopped traffic for a few minutes when it would creep towards 90°C and then drop again as soon as I started moving.
All good after putting in a new main thermostat. Up to 90°C on the dash in about 7 minutes now.

Do you plan on changing it yourself?

Im not too sure yet, hadnt thought too much about it as really want to confirm if it is causing an issue.

As I say, mine gets to temp on the clocks in no time and stays at a solid 90°, its the 'secret menu' in the AC that shows a true reading of 77-82° and never higher.

Offline The Red Warrior

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Re: Possible Thermostat Issue
« Reply #14 on: June 30, 2017, 01:27:56 am »
Sorry, re-read your post and symptoms are different to mine. Dunno what mine(standard GTI) sits at on digital gauge anymore as changed to mk6 climatronic unit. Someone here with an ED30 should be able to tell you.