Overheated - panic stations?

Kroll · 20th December 2022, 14:27

My 1.8t ZT got a little warm on Sunday afternoon during a drive back from a hospital appointment. The temp gauge blipped into the red, the warning flashed up for a second and then immediately went back to normal.

I’ve not been well so only had the chance to check on things properly this afternoon. Oil levels seem fine, but coolant levels were way down. I’ve filled that up and will see if it goes down again.

There’s no sign of the dreaded mayonnaise, but I know that’s not the be all and end all of HGF diagnosis.

Is it likely the cold snap and fast thaw we experienced this last week could have caused a leak somewhere? Or is this just wishful thinking? The only other symptoms I’ve had are the heating taking a while to kick in, but I put that down to the weather.

What other checks and precautions should I take? I’m just looking for advice and reassurance really.

The Rovering Member · 20th December 2022, 14:33

My 1.8 n/a overheated once due to low coolant but after a quick garage stop & top-up there were no further issues.

SD1too · 20th December 2022, 18:29

Quote:

Originally Posted by Kroll

What other checks and precautions should I take? I’m just looking for advice and reassurance really.

Do the "demist test" Tom to check that your fan is working on slow speed.

Start the engine from cold.
Press the windscreen demist button on the air con./heater control panel.
Get out of the car and walk to the radiator grille.
Can you hear the fan running continuously?

Simon

Kroll · 21st December 2022, 15:21

Quote:

Originally Posted by SD1too

Do the "demist test" Tom to check that your fan is working on slow speed.

Start the engine from cold.
Press the windscreen demist button on the air con./heater control panel.
Get out of the car and walk to the radiator grille.
Can you hear the fan running continuously?

Simon

Yeah the fan seems to be working ok. I decided to drive it to the shop and back this morning, (only around a mile or so.) Didn’t skip a beat, and there was no issue with temperature.

It’s lost all the coolant I stuck in it yesterday though, so there’s an issue somewhere within the coolant system I’m guessing? Any suggestions on what to look at next?

DMGRS · 21st December 2022, 15:49

It sounds like a coolant loss issue to me - when the level is low, the heaters will feel 'lukewarm' as they're quite high up in the coolant circuit.

A good place to start with a 1.8 (assuming you have the plastic inlet manifold) is the inlet manifold gasket - these go hard with age and start to leak.
Sometimes they leak into cylinder 1, so there's no external indication you're losing coolant!
We have the revised Viton gasket designed to last a lot longer here: https://www.dmgrs.co.uk/products/k-s...sket-lkj101110

Another source of coolant loss is the O Rings in the coolant cap; they flatten with age, allowing steam to escape at higher pressures when on the move.
Again, hard to spot as the loss is often gradual.
You can get replacements here: https://www.dmgrs.co.uk/products/rov...to-fix-esr1480

These issues probably account for a good 50% of K Series coolant loss episodes we're asked to help diagnose these days - very common, but thankfully both relatively simple repairs.

Kroll · 22nd December 2022, 14:29

Quote:

Originally Posted by DMGRS

It sounds like a coolant loss issue to me - when the level is low, the heaters will feel 'lukewarm' as they're quite high up in the coolant circuit.

A good place to start with a 1.8 (assuming you have the plastic inlet manifold) is the inlet manifold gasket - these go hard with age and start to leak.
Sometimes they leak into cylinder 1, so there's no external indication you're losing coolant!
We have the revised Viton gasket designed to last a lot longer here: https://www.dmgrs.co.uk/products/k-s...sket-lkj101110

Another source of coolant loss is the O Rings in the coolant cap; they flatten with age, allowing steam to escape at higher pressures when on the move.
Again, hard to spot as the loss is often gradual.
You can get replacements here: https://www.dmgrs.co.uk/products/rov...to-fix-esr1480

These issues probably account for a good 50% of K Series coolant loss episodes we're asked to help diagnose these days - very common, but thankfully both relatively simple repairs.

Thanks will look into this too.

Kroll · 18th January 2023, 10:44

Little update. After a busy Christmas period, and a bout of illness, I finally got to take the ZT out for a proper spin yesterday evening. Managed about 20 miles, no overheating issue, and the cabin heating was consistently lovely and warm.

Have checked coolant levels this morning and it all looks good. So hoping this is as simple as it being the coolant cap. I’ve ordered the O rings and will see how we go from there.

Fingers crossed.

Kroll · 21st March 2024, 15:42

Sorry to dig up my old thread, but it’s high time I sorted this issue. Since I’ve only been using the old girl to nip to the co-op and back I’ve left this far too long.

I’ve tried replacing the coolant cap, but it’s still losing the coolant over the course of around 10 days - 2 weeks. Car never gets to the point it overheats, so it was just the original incident I mentioned all those months ago.

I have noticed a little bit of mayo on the oil cap today, does this always mean HGF? Or would a perished inlet manifold gasket allow water to get into the oil? I have had it suggested that this could just be condensation from the minimal use the car gets?

If not, my next step is to change the inlet manifold gasket as suggested. Is this as simple a job as it looks? Just disconnecting, cleaning things up nicely and then fitting it all back together?

As ever any help and tips are greatly appreciated.

SD1too · 21st March 2024, 17:20

Before we get into the drama of head gasket failure, consider this:

Quote:

Originally Posted by Kroll

... I’ve only been using the old girl to nip to the co-op and back ...

Quote:

Originally Posted by Kroll

... only around a mile or so.

Tom; as Steve has said, that's barely enough for the engine to reach normal temperature which may well explain the small amount of mayonnaise under the oil filler cap.

In post no. 8 I recommended use of the instrument pack diagnostics to discover whether or not the engine is reaching a proper temperature during your very short drives to the Co-Op. Did you ever do that?
If not, can you do it now?

Simon

SD1too · 22nd December 2022, 06:54

Quote:

Originally Posted by Kroll

Yeah the fan seems to be working ok ... Any suggestions on what to look at next?

Activate the instrument pack diagnostics, test 7.0, to monitor the actual coolant temperature whilst driving. It should rise to the low nineties and stabilise there unless you're stationary in traffic. In that event it will creep up to 104˚ when the fan should bring it down.

I need to ask whether anyone's been working on the cooling system recently or whether K-Seal has been put in to the cooling system.

Simon

20th December 2022, 14:27	#1
Kroll Regular poster ZT 160 Join Date: Sep 2021 Location: West Wales Posts: 80 Thanks: 33 Thanked 15 Times in 12 Posts	Overheated - panic stations? My 1.8t ZT got a little warm on Sunday afternoon during a drive back from a hospital appointment. The temp gauge blipped into the red, the warning flashed up for a second and then immediately went back to normal. I’ve not been well so only had the chance to check on things properly this afternoon. Oil levels seem fine, but coolant levels were way down. I’ve filled that up and will see if it goes down again. There’s no sign of the dreaded mayonnaise, but I know that’s not the be all and end all of HGF diagnosis. Is it likely the cold snap and fast thaw we experienced this last week could have caused a leak somewhere? Or is this just wishful thinking? The only other symptoms I’ve had are the heating taking a while to kick in, but I put that down to the weather. What other checks and precautions should I take? I’m just looking for advice and reassurance really.

20th December 2022, 14:33	#2
The Rovering Member I really should get out more....... Rover 75 saloon Join Date: Feb 2014 Location: London Posts: 2,963 Thanks: 263 Thanked 538 Times in 431 Posts	My 1.8 n/a overheated once due to low coolant but after a quick garage stop & top-up there were no further issues. __________________ Reducing the size of my Rover fleet by adding a 75 to it.

21st December 2022, 15:49	#5
DMGRS Discount MG Rover Spares Rover 75 CDTi, 2x MG ZS180 Join Date: Jun 2011 Location: Hythe, Southampton Posts: 11,321 Thanks: 456 Thanked 3,377 Times in 2,027 Posts	It sounds like a coolant loss issue to me - when the level is low, the heaters will feel 'lukewarm' as they're quite high up in the coolant circuit. A good place to start with a 1.8 (assuming you have the plastic inlet manifold) is the inlet manifold gasket - these go hard with age and start to leak. Sometimes they leak into cylinder 1, so there's no external indication you're losing coolant! We have the revised Viton gasket designed to last a lot longer here: https://www.dmgrs.co.uk/products/k-s...sket-lkj101110 Another source of coolant loss is the O Rings in the coolant cap; they flatten with age, allowing steam to escape at higher pressures when on the move. Again, hard to spot as the loss is often gradual. You can get replacements here: https://www.dmgrs.co.uk/products/rov...to-fix-esr1480 These issues probably account for a good 50% of K Series coolant loss episodes we're asked to help diagnose these days - very common, but thankfully both relatively simple repairs. __________________ Your trusted MG Rover specialist! Tel: 02380 001133 / Email: [email protected] We now have a 'chat' function on our site for even quicker replies. Give it a try! Remember - discount code FORUM5 for 5% off

18th January 2023, 10:44	#7
Kroll Regular poster ZT 160 Join Date: Sep 2021 Location: West Wales Posts: 80 Thanks: 33 Thanked 15 Times in 12 Posts	Little update. After a busy Christmas period, and a bout of illness, I finally got to take the ZT out for a proper spin yesterday evening. Managed about 20 miles, no overheating issue, and the cabin heating was consistently lovely and warm. Have checked coolant levels this morning and it all looks good. So hoping this is as simple as it being the coolant cap. I’ve ordered the O rings and will see how we go from there. Fingers crossed.

21st March 2024, 15:42	#8
Kroll Regular poster ZT 160 Join Date: Sep 2021 Location: West Wales Posts: 80 Thanks: 33 Thanked 15 Times in 12 Posts	Sorry to dig up my old thread, but it’s high time I sorted this issue. Since I’ve only been using the old girl to nip to the co-op and back I’ve left this far too long. I’ve tried replacing the coolant cap, but it’s still losing the coolant over the course of around 10 days - 2 weeks. Car never gets to the point it overheats, so it was just the original incident I mentioned all those months ago. I have noticed a little bit of mayo on the oil cap today, does this always mean HGF? Or would a perished inlet manifold gasket allow water to get into the oil? I have had it suggested that this could just be condensation from the minimal use the car gets? If not, my next step is to change the inlet manifold gasket as suggested. Is this as simple a job as it looks? Just disconnecting, cleaning things up nicely and then fitting it all back together? As ever any help and tips are greatly appreciated.