Running temperature of 1800 motor with NO thermostat

Post Reply
Dayknight-VW
Cadet
Posts: 55
Registered for: 11 years 2 months

Running temperature of 1800 motor with NO thermostat

Post by Dayknight-VW »

Howsit guys… so I finally built my 1800 motor, was originally 1.4, rebored the block, changed crank and pistons. Car is running nice but I have a question which puzzles me a bit.

I have no thermostat into the vehicle, when it was 1.4 it used to run cold once I get onto the freeway or a open road. Now with the 1800 setup it’s doesn’t drop past quarter on the heat guage when I’m on a open road, sits over quarter just before half, that’s about the coldest it runs. Is this a cause for concern? Cooling system seems fine in the vehicle no issues.

I know it’s not healthy to let the engine run cold but I’m just curious as to why this motor is running so hot even with no thermostat compared to the 1.4 and do I have anything to worry about.

Thanks in advance
User avatar
Unobeat
Lieutenant-General
Posts: 8378
Registered for: 12 years 11 months
Car Make: Fiat, Toyota, Mazda
Car Model: Uno, Auris, CX-5
Location: Pretoria

Re: Running temperature of 1800 motor with NO thermostat

Post by Unobeat »

Why though, are you running the engine without a Thermostat because engineers designed an engine to have a Thermostat because it has an important function in the cooling system functionality.

Sent from my SM-A307FN using Tapatalk

THANAS wrote:Mix them together to create Shellstrol, and then mix that with Winstrol to create the ultimate, maximum performance oil for your engine.
panic-mechanic wrote:When I build engines and do stuff like this I do it when there is nobody else around, No distractions, No phone nothing so that you don't forget what you should be doing. It's the little things that make them run right. Anybody can slap a basic bottom end together. that is the easy bit. It's all the little things that makes these builds a success or not.
User avatar
Unobeat
Lieutenant-General
Posts: 8378
Registered for: 12 years 11 months
Car Make: Fiat, Toyota, Mazda
Car Model: Uno, Auris, CX-5
Location: Pretoria

Re: Running temperature of 1800 motor with NO thermostat

Post by Unobeat »

*double post*
THANAS wrote:Mix them together to create Shellstrol, and then mix that with Winstrol to create the ultimate, maximum performance oil for your engine.
panic-mechanic wrote:When I build engines and do stuff like this I do it when there is nobody else around, No distractions, No phone nothing so that you don't forget what you should be doing. It's the little things that make them run right. Anybody can slap a basic bottom end together. that is the easy bit. It's all the little things that makes these builds a success or not.
User avatar
EX-DOHCTOR
Field Marshal
Posts: 13737
Registered for: 19 years 4 months
Car Make: VW
Car Model: 2014 Jetta 6 TDi DSG.
Membership No: 712
Location: Bryanston, Johannesburg
Contact:

Re: Running temperature of 1800 motor with NO thermostat

Post by EX-DOHCTOR »

I'd also like to know why you're not running with a Thermostat. I'd get on in there pronto.

Are you running correct coolant (G12) in the correct ratio atleast?
2014 - VW Jetta 6 - 1.6 TDi DSG
2000 - VW Golf 3.5 Cabrio - 2.0
1980 - VW MK1 GT - 1.8 Carb - https://www.vwclub.co.za/forum/viewtopi ... 1&t=153861
1971 - Mitsubishi Colt 1100F - https://www.vwclub.co.za/forum/viewtopi ... 1&t=220503
MK1 Build Register: https://www.vwclub.co.za/forum/viewtopi ... 1&t=192835
Instagram: https://www.instagram.com/projectkirschwasser/

Racing is meant for the RACE track - deal with it...
Howie-WP
VWCSA Member
Posts: 14200
Registered for: 21 years 7 months
Membership No: 2033
Location: Cape Town, SA

Re: Running temperature of 1800 motor with NO thermostat

Post by Howie-WP »

EX-DOHCTOR wrote: Fri Oct 15, 2021 3:00 pm I'd also like to know why you're not running with a Thermostat.
Because..... sounds cool when braai talking :oops: :troll:
Dayknight-VW
Cadet
Posts: 55
Registered for: 11 years 2 months

Re: Running temperature of 1800 motor with NO thermostat

Post by Dayknight-VW »

Car never had a thermostat initially, as I said I know it’s not healthy to run without it, I was just curious about the change in temperatures after I changed to 1800
Greenz
Captain
Posts: 2036
Registered for: 10 years 2 months
Car Make: Ford
Car Model: Focus ST
Location: Pietermaritzburg

Re: Running temperature of 1800 motor with NO thermostat

Post by Greenz »

It doesn't even reach operating temperature.I doubt there is anything to "worry" about.That is assuming your guage is accurate.
2010 ST225 - 238kw 439nm
mellos
Cadet
Posts: 245
Registered for: 7 years 8 months
Location: Pietermaritzburg

Re: Running temperature of 1800 motor with NO thermostat

Post by mellos »

Greenz wrote:It doesn't even reach operating temperature.I doubt there is anything to "worry" about.That is assuming your guage is accurate.
Good day

When you rebore an engine the cooling jackets around the pistons is made thinner, hence more heat is being generated, the thermostat is there for the engine to reach operating temperature as quick as possible and to maintain that temperature, having the car run hot and cold is not good for an engine,personally I would put that thermostat back asap, and as far as I know VW operating temperature is at 90 degrees as the guage is sitting upright at all times, just my 50 cents.

Sent from my ANE-LX1 using Tapatalk

JCTPUBLISHERS
Cadet
Posts: 220
Registered for: 3 years 8 months

Re: Running temperature of 1800 motor with NO thermostat

Post by JCTPUBLISHERS »

Dangers of removing a thermostat from an engine:
The engine may run at too low temperature, with resultant long-term damage.
The engine may overheat under severe conditions, as the water will circulate too quickly to be cooled effectively without the restrictive effect of a thermostat.
The circulation of the cooling water may be impaired especially in the cylinder head, even though the temp gauge( whose sending unit is usually mounted at the front of the cylinder head) may indicated "normal". However, localised overheating could occur at the rear of the thermostat.
All above as Mellos stated
JCTPUBLISHERS
Cadet
Posts: 220
Registered for: 3 years 8 months

Re: Running temperature of 1800 motor with NO thermostat

Post by JCTPUBLISHERS »

Info can also be found in any N1: Motor Trade Theory textbook.
Greenz
Captain
Posts: 2036
Registered for: 10 years 2 months
Car Make: Ford
Car Model: Focus ST
Location: Pietermaritzburg

Re: Running temperature of 1800 motor with NO thermostat

Post by Greenz »

mellos wrote: Sun Oct 17, 2021 8:30 am
Greenz wrote:It doesn't even reach operating temperature.I doubt there is anything to "worry" about.That is assuming your guage is accurate.
Good day

When you rebore an engine the cooling jackets around the pistons is made thinner, hence more heat is being generated, the thermostat is there for the engine to reach operating temperature as quick as possible and to maintain that temperature, having the car run hot and cold is not good for an engine,personally I would put that thermostat back asap, and as far as I know VW operating temperature is at 90 degrees as the guage is sitting upright at all times, just my 50 cents.

Sent from my ANE-LX1 using Tapatalk
Thank you.From his question,it seems like he is worried that it may be overheating compared to when he still was 1.4 which is why i said "worry".But yes,would be wise to put in a thermostat.
2010 ST225 - 238kw 439nm
User avatar
EX-DOHCTOR
Field Marshal
Posts: 13737
Registered for: 19 years 4 months
Car Make: VW
Car Model: 2014 Jetta 6 TDi DSG.
Membership No: 712
Location: Bryanston, Johannesburg
Contact:

Re: Running temperature of 1800 motor with NO thermostat

Post by EX-DOHCTOR »

Are you running coolant in the system of this engine?
2014 - VW Jetta 6 - 1.6 TDi DSG
2000 - VW Golf 3.5 Cabrio - 2.0
1980 - VW MK1 GT - 1.8 Carb - https://www.vwclub.co.za/forum/viewtopi ... 1&t=153861
1971 - Mitsubishi Colt 1100F - https://www.vwclub.co.za/forum/viewtopi ... 1&t=220503
MK1 Build Register: https://www.vwclub.co.za/forum/viewtopi ... 1&t=192835
Instagram: https://www.instagram.com/projectkirschwasser/

Racing is meant for the RACE track - deal with it...
Dayknight-VW
Cadet
Posts: 55
Registered for: 11 years 2 months

Re: Running temperature of 1800 motor with NO thermostat

Post by Dayknight-VW »

Thanks for help guys. No I didn’t add coolant yet. Still running in the motor
User avatar
EX-DOHCTOR
Field Marshal
Posts: 13737
Registered for: 19 years 4 months
Car Make: VW
Car Model: 2014 Jetta 6 TDi DSG.
Membership No: 712
Location: Bryanston, Johannesburg
Contact:

Re: Running temperature of 1800 motor with NO thermostat

Post by EX-DOHCTOR »

You're running just water after the rebore and rebuild??
2014 - VW Jetta 6 - 1.6 TDi DSG
2000 - VW Golf 3.5 Cabrio - 2.0
1980 - VW MK1 GT - 1.8 Carb - https://www.vwclub.co.za/forum/viewtopi ... 1&t=153861
1971 - Mitsubishi Colt 1100F - https://www.vwclub.co.za/forum/viewtopi ... 1&t=220503
MK1 Build Register: https://www.vwclub.co.za/forum/viewtopi ... 1&t=192835
Instagram: https://www.instagram.com/projectkirschwasser/

Racing is meant for the RACE track - deal with it...
User avatar
missioner
Major
Posts: 3987
Registered for: 10 years 3 months
Car Make: VW
Car Model: '87 MK1 Golf Citi

Re: Running temperature of 1800 motor with NO thermostat

Post by missioner »

Aside from the thermostat issue, I noticed the same effect after the rebore of my motor.

The reason is explained in a previous post so I won't repeat it.

The end solution was a bigger radiator.

Sent from my M2101K6G using Tapatalk

'87 Golf 1 Olde Skewl OEM+
User avatar
EX-DOHCTOR
Field Marshal
Posts: 13737
Registered for: 19 years 4 months
Car Make: VW
Car Model: 2014 Jetta 6 TDi DSG.
Membership No: 712
Location: Bryanston, Johannesburg
Contact:

Re: Running temperature of 1800 motor with NO thermostat

Post by EX-DOHCTOR »

missioner wrote: Mon Oct 18, 2021 1:26 pmThe end solution was a bigger radiator.
Sent from my M2101K6G using Tapatalk
MK2 large radiator?
2014 - VW Jetta 6 - 1.6 TDi DSG
2000 - VW Golf 3.5 Cabrio - 2.0
1980 - VW MK1 GT - 1.8 Carb - https://www.vwclub.co.za/forum/viewtopi ... 1&t=153861
1971 - Mitsubishi Colt 1100F - https://www.vwclub.co.za/forum/viewtopi ... 1&t=220503
MK1 Build Register: https://www.vwclub.co.za/forum/viewtopi ... 1&t=192835
Instagram: https://www.instagram.com/projectkirschwasser/

Racing is meant for the RACE track - deal with it...
User avatar
missioner
Major
Posts: 3987
Registered for: 10 years 3 months
Car Make: VW
Car Model: '87 MK1 Golf Citi

Re: Running temperature of 1800 motor with NO thermostat

Post by missioner »

EX-DOHCTOR wrote:
missioner wrote: Mon Oct 18, 2021 1:26 pmThe end solution was a bigger radiator.
Sent from my M2101K6G using Tapatalk
MK2 large radiator?
Yes that one.

Sent from my M2101K6G using Tapatalk

'87 Golf 1 Olde Skewl OEM+
User avatar
markfish888
Cadet
Posts: 595
Registered for: 12 years 11 months
Car Make: VW
Car Model: B7A4 -JETTA Mk2
Membership No: 1787
Location: Faerie Glen PRETORIA

Re: Running temperature of 1800 motor with NO thermostat

Post by markfish888 »

With EFi, ecu will think car is cold, will overfuel .
Apart from the horrendously bad fuel economy, will wash oil of your cylinder bores.

My brother in law, removed thermostat in his kia sportage 1st gen, His GF complained was running hot in traffic.
We did a Jhb to kroonstad trip.

Filled tank. 300km later: We ran out of juice on the way back, between the Shell & engen garage on N1 north.

After a Cape Town truck picked him up to get juice at the engen( he was wearing his stormer jersey, only time I was happy about the stormers )
We got going again, and I Saw the temp gauge sat @ 1/4 of range.

IMcGuyverd a piece of cardboard in front of radiator, to get car to correct operating temp, fuel economy drastically improved.
MK2's dont die, they just get faster!!

Image
Post Reply