Overheating/coolant loss

Shez2908 · 9th April 2020, 10:05

Hi, had my MGZT from new 2004, had a new engine fitted 2years ago. I've recently had it in the garage for coolant loss and overheating. Apparently the fan was faulty and they replaced the resistor and relay cost £400 as a lot of labour involved. Had it back and 2 weeks on there still lots of pressure in system and coolant overflowing from radiator tank!..The fan is kicking in but hasn't solved the problem of my engine overheating!.Rang garage (they know the car well as have done all my work over the years). They say it has to be the head Gasket!..which will prob cost another 400..he is trying to persuade me to get rid and get another car. Problem is I love the car!...and it's worth every penny to me. I would just like some thoughts/Advice as to whether getting the head gasket replaced will cure the problem??..I was always under the assumption that there would be signs of that failing when removing the oil cap, like a milky residue?..it sounds daft but it runs smoothly and no oil loss, can the head still fail without those signs?..just don't want to spend hundreds more to find there's something else underlying!. Many Thanks Sheran.

thanos.m · 9th April 2020, 11:00

Your profile says that your car is a 1.8 please confirm that with us. When you say it overheated did you see the temp gauge shooting up because when it does things are actually already quite hot. If it is the 1.8 I've found that in many K-seires engines first signs of an hgf is oil in the coolant. When you say there is a lot of pressure does the cooland appear to be "boiling" that would indicate that exhaust gases are going in the coolant so you indeed have a hgf. Additionally, you can have a hgf without the common signs it really depends how the hg has failed. Before you do anything please have a propair diagnosis because the amount of rover head gaskets that have been replaced without actually needing replacement is quite scary. Now if the head gasket is gone and the car is generally in good shape I would say go ahead and have it done it will be a piece of mind you'll know its done and you'll have a ZT that will good for many more years to come!

coolguy · 9th April 2020, 11:18

Cannot comment on the technical issue (I am no mechanic), but if you love the car, which you obviously do, I would attempt to get a correct diagnosis from one of our knowledgeable guys on here and spend on it - far cheaper than buying a load of modern rubbish!

Yorkshire GOC · 9th April 2020, 12:07

A simple test for HGF - give her a good thrash (if you can) - 5 miles at speed - then leave her overnight - then open the expansion tank - if you get the hiss/whoosh of gas escaping this shows pressure in a cold system and points to exhaust gas having leaked into the coolant system pointing to HGF. Also sniff the expansion tank to see if you smell exhaust fumes.

However you are correct that the classic symptoms to expect are mayonaise on your dip stick and under the oil filler cap.

Alternatively you also could have an airlock in the coolant system

Shez2908 · 9th April 2020, 15:08

Hi..yes it's the ZT 120..1796cc. The guage was shooting up so I was then pulling over waited and looked under the bonnet.. The radiator feeder tank was bubbling with coolant overflowing!.and the fan was still going..It is in great condition so is worth far more to me. I will try and sought a Rover/MG specialist to get another opinion!.
Thanks very helpful!.

Shez2908 · 9th April 2020, 15:18

Thanks. Yes my sentiments exactly!..it's a great shape car and there's nothing else that I would want..plus no guarantees that I wouldn't be buying something that needed spending on!..��

Shez2908 · 9th April 2020, 15:43

Quote:

Originally Posted by Yorkshire GOC

A simple test for HGF - give her a good thrash (if you can) - 5 miles at speed - then leave her overnight - then open the expansion tank - if you get the hiss/whoosh of gas escaping this shows pressure in a cold system and points to exhaust gas having leaked into the coolant system pointing to HGF. Also sniff the expansion tank to see if you smell exhaust fumes.

However you are correct that the classic symptoms to expect are mayonaise on your dip stick and under the oil filler cap.

Alternatively you also could have an airlock in the coolant system

Hi..Yes I did do that but was fine in the morning?..no hissing etc, but had lost coolant and needed topping up.I mentioned the sniff test to the garage and they said it was ok, which is why I'm not convinced it's that!.prob a daft question but can they tell it's the hg or is it only diagnosed by symptoms. Thanks for the advice!.

suzublu · 9th April 2020, 16:02

Durham eh? Dave Johnson at Fencehouses is your man

Any raises in coolant temp usually points to a leak, points to look at are Inlet manifold gasket, water pump, thermostat. Also you can run the temp. diagnostic on the obd thus https://the75andztclub.co.uk/forum/s...ad.php?t=55585
19 and 7 are the numbers you need.

PS every garage that sees a 1.8 K series immediately says head gasket, it's a cop-out

Cosmin161 · 9th April 2020, 18:28

Hi, if you have problems with the cooling system you shouldn't drive it hard as k engines warp when overheated.
With a cold engine, remove the coolant tank cap, start the engine, then place your hand over the coolant tank for about 10 seconds and check if any pressure accumulated when you lift your hand. If there is pressure in the coolant tank when both engine and coolant are cold it means that gases from the cylinders enter the cooling system through a failed hg. If not, the thermostat might be blocked and the water doesn't circulate through the long circuit and doesn't reach the radiator. To test this start the engine, wait for the temperature to rise then put your hand on the radiator and check if its hot. Watch out for the cooling fan as it may start any time. If the radiator is cold but the coolant gauge is up it means that coolant doesn't reach the radiator and you should replace the thermostat. If the radiator is hot it means that coolant isn't circulated through the system fast enough inicating a failed water pump.

Shez2908 · 9th April 2020, 21:58

Quote:

Originally Posted by suzublu

Durham eh? Dave Johnson at Fencehouses is your man

Any raises in coolant temp usually points to a leak, points to look at are Inlet manifold gasket, water pump, thermostat. Also you can run the temp. diagnostic on the obd thus https://the75andztclub.co.uk/forum/s...ad.php?t=55585
19 and 7 are the numbers you need.

PS every garage that sees a 1.8 K series immediately says head gasket, it's a cop-out

Ah thanks!..I'll get in touch..not too far from me.Yes water pump and thermostat recently renewed!..and you're spot on about K Series engines!.ha!.a few I've mentioned it to have had the same response! "Oooh K Series Engine,it'll be the hg"!!..Thanks for info.

9th April 2020, 10:05	#1
Shez2908 Newbie MGZT Join Date: Aug 2019 Location: Sedgefield County Durham Posts: 18 Thanks: 6 Thanked 2 Times in 2 Posts	Overheating/coolant loss Hi, had my MGZT from new 2004, had a new engine fitted 2years ago. I've recently had it in the garage for coolant loss and overheating. Apparently the fan was faulty and they replaced the resistor and relay cost £400 as a lot of labour involved. Had it back and 2 weeks on there still lots of pressure in system and coolant overflowing from radiator tank!..The fan is kicking in but hasn't solved the problem of my engine overheating!.Rang garage (they know the car well as have done all my work over the years). They say it has to be the head Gasket!..which will prob cost another 400..he is trying to persuade me to get rid and get another car. Problem is I love the car!...and it's worth every penny to me. I would just like some thoughts/Advice as to whether getting the head gasket replaced will cure the problem??..I was always under the assumption that there would be signs of that failing when removing the oil cap, like a milky residue?..it sounds daft but it runs smoothly and no oil loss, can the head still fail without those signs?..just don't want to spend hundreds more to find there's something else underlying!. Many Thanks Sheran.

9th April 2020, 12:07	#4
Yorkshire GOC I really should get out more....... Rover 75 connoisseur se v6 auto Join Date: May 2014 Location: Hull Posts: 2,063 Thanks: 1,842 Thanked 623 Times in 469 Posts	A simple test for HGF - give her a good thrash (if you can) - 5 miles at speed - then leave her overnight - then open the expansion tank - if you get the hiss/whoosh of gas escaping this shows pressure in a cold system and points to exhaust gas having leaked into the coolant system pointing to HGF. Also sniff the expansion tank to see if you smell exhaust fumes. However you are correct that the classic symptoms to expect are mayonaise on your dip stick and under the oil filler cap. Alternatively you also could have an airlock in the coolant system __________________ She came off the Longbridge Line on 20-05-2003 The Silver Machine was the 13th of 160 Rover 75's to come off the production line that day and is the 100th of 527 Starlight Silver Rover 75 2.5 V6 Connoisseur SE Auto saloons listed in the build records produced world wide.

9th April 2020, 15:08	#5
Shez2908 Newbie MGZT Join Date: Aug 2019 Location: Sedgefield County Durham Posts: 18 Thanks: 6 Thanked 2 Times in 2 Posts	Hi..yes it's the ZT 120..1796cc. The guage was shooting up so I was then pulling over waited and looked under the bonnet.. The radiator feeder tank was bubbling with coolant overflowing!.and the fan was still going..It is in great condition so is worth far more to me. I will try and sought a Rover/MG specialist to get another opinion!. Thanks very helpful!. Last edited by Shez2908; 9th April 2020 at 15:21..

9th April 2020, 11:00	#2
thanos.m Avid contributor Rover 75 saloon Join Date: May 2019 Location: West Sussex Posts: 220 Thanks: 54 Thanked 41 Times in 26 Posts	Your profile says that your car is a 1.8 please confirm that with us. When you say it overheated did you see the temp gauge shooting up because when it does things are actually already quite hot. If it is the 1.8 I've found that in many K-seires engines first signs of an hgf is oil in the coolant. When you say there is a lot of pressure does the cooland appear to be "boiling" that would indicate that exhaust gases are going in the coolant so you indeed have a hgf. Additionally, you can have a hgf without the common signs it really depends how the hg has failed. Before you do anything please have a propair diagnosis because the amount of rover head gaskets that have been replaced without actually needing replacement is quite scary. Now if the head gasket is gone and the car is generally in good shape I would say go ahead and have it done it will be a piece of mind you'll know its done and you'll have a ZT that will good for many more years to come!

9th April 2020, 11:18	#3
coolguy Coolguy Rover 75 CDT Tourer Auto, Rover 75 2.0 Connoisseur Auto, MG ZT 2.5 Auto and MG ZT Cdti Auto (Monogra Join Date: Nov 2009 Location: Finedon Posts: 1,896 Thanks: 933 Thanked 638 Times in 430 Posts	Cannot comment on the technical issue (I am no mechanic), but if you love the car, which you obviously do, I would attempt to get a correct diagnosis from one of our knowledgeable guys on here and spend on it - far cheaper than buying a load of modern rubbish!

9th April 2020, 15:18	#6
Shez2908 Newbie MGZT Join Date: Aug 2019 Location: Sedgefield County Durham Posts: 18 Thanks: 6 Thanked 2 Times in 2 Posts	Thanks. Yes my sentiments exactly!..it's a great shape car and there's nothing else that I would want..plus no guarantees that I wouldn't be buying something that needed spending on!..��

9th April 2020, 16:02	#8
suzublu This is my second home rover 75 1.8 vvc club se wedgwood blue Join Date: Aug 2009 Location: Seaton Carew Posts: 26,912 Thanks: 65 Thanked 7,142 Times in 4,642 Posts	Durham eh? Dave Johnson at Fencehouses is your man Any raises in coolant temp usually points to a leak, points to look at are Inlet manifold gasket, water pump, thermostat. Also you can run the temp. diagnostic on the obd thus https://the75andztclub.co.uk/forum/s...ad.php?t=55585 19 and 7 are the numbers you need. PS every garage that sees a 1.8 K series immediately says head gasket, it's a cop-out

9th April 2020, 18:28	#9
Cosmin161 Newbie Rover 75 RJ Join Date: Apr 2020 Location: Ruseni Posts: 22 Thanks: 7 Thanked 5 Times in 3 Posts	Hi, if you have problems with the cooling system you shouldn't drive it hard as k engines warp when overheated. With a cold engine, remove the coolant tank cap, start the engine, then place your hand over the coolant tank for about 10 seconds and check if any pressure accumulated when you lift your hand. If there is pressure in the coolant tank when both engine and coolant are cold it means that gases from the cylinders enter the cooling system through a failed hg. If not, the thermostat might be blocked and the water doesn't circulate through the long circuit and doesn't reach the radiator. To test this start the engine, wait for the temperature to rise then put your hand on the radiator and check if its hot. Watch out for the cooling fan as it may start any time. If the radiator is cold but the coolant gauge is up it means that coolant doesn't reach the radiator and you should replace the thermostat. If the radiator is hot it means that coolant isn't circulated through the system fast enough inicating a failed water pump.