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ricebridge · 4th November 2018, 09:11

Hi everyone!
My 2002 ZT-T, which I just bought, tends to suddenly shoot its temp gauge to max and warn of engine overheating. It seems to be losing coolant as well. Or does it?
Having read through some similar problems here on the forum, I understand it’s not uncommon with these engines. Then again, I’m worrying about HGF and would be grateful for any advice or help.

So let me explain the symptoms in detail:

I drove it home on a 1,000+ km trip from where I bought it, with plenty of motorway driving. During this trip, I must have put in at least 4 litres of coolant. Is 0.04 ml per km a lot? And where did it all go?

I first thought it must be a faulty sensor somewhere. Or could it be the thermostat? According to the service history, it was replaced only some 3,000 kms ago. Good or bad?

The heater seems to put out most of the heat around my feet. That would mean an air lock, wouldn’t it?

I just drained the system and replaced the coolant, being careful to bleed it all just the way Uncle Haynes tells me to. But the problem is still there. Or, at least it was during my test drive late last night. The expansion tank was half full (or half empty, for those so inclined

) — if the coolant is escaping somewhere, how come the tank, which is at the highest level, still contains coolant? (Last time I looked, fluids ran downwards...) This was the first time I did it on any MGR. Did I get it wrong after all, and create a new air lock?

I checked the engine oil, although I did not loosen the drain plug and take a larger sample. But around the dipstick it was perfectly fine, and when I stuck my finger inside the engine at the filler hole after removing the filler cap, the oil I could touch there was just as good.

On the inside of the filler cap, however, there was indeed some ”mustard” (yellowish sludge), perhaps half a teaspoon of the stuff, absolutely no more. That set the HGF alarm bells off in my wallet, but then again, I understand that there could be other reasons for such stuff to build up over time (clasping at straws here...) And shouldn’t there be more, and shouldn’t there be sludge elsewhere too, in case of a HGF?

I’ve checked all over the engine for coolant residue, but the results were inconclusive. However, I did notice that one copperish-looking pipe (bear with me pls for not knowing all the exact technical terms here) that goes across the engine below it at the front, and which is connected to the hose leading down from the expansion tank, was greenish. Is that even an original part? Why put a piece of copper pipe into a hose-based cooling system? Won’t that cause corrosion from aluminium parts?

There’s no misfiring, and I can see no white smoke from the tailpipe when driving, although I do tend to sit at the front of the car when driving, so visibility of the exhaust is somewhat limited...

Grateful for any help or comment!

4th November 2018, 09:11	#1
ricebridge Avid contributor MG ZT-T Join Date: Oct 2018 Location: Bankeryd, Sweden Posts: 100 Thanks: 61 Thanked 11 Times in 10 Posts	KV6 overheating and losing coolant Hi everyone! My 2002 ZT-T, which I just bought, tends to suddenly shoot its temp gauge to max and warn of engine overheating. It seems to be losing coolant as well. Or does it? Having read through some similar problems here on the forum, I understand it’s not uncommon with these engines. Then again, I’m worrying about HGF and would be grateful for any advice or help. So let me explain the symptoms in detail: I drove it home on a 1,000+ km trip from where I bought it, with plenty of motorway driving. During this trip, I must have put in at least 4 litres of coolant. Is 0.04 ml per km a lot? And where did it all go? I first thought it must be a faulty sensor somewhere. Or could it be the thermostat? According to the service history, it was replaced only some 3,000 kms ago. Good or bad? The heater seems to put out most of the heat around my feet. That would mean an air lock, wouldn’t it? I just drained the system and replaced the coolant, being careful to bleed it all just the way Uncle Haynes tells me to. But the problem is still there. Or, at least it was during my test drive late last night. The expansion tank was half full (or half empty, for those so inclined ) — if the coolant is escaping somewhere, how come the tank, which is at the highest level, still contains coolant? (Last time I looked, fluids ran downwards...) This was the first time I did it on any MGR. Did I get it wrong after all, and create a new air lock? I checked the engine oil, although I did not loosen the drain plug and take a larger sample. But around the dipstick it was perfectly fine, and when I stuck my finger inside the engine at the filler hole after removing the filler cap, the oil I could touch there was just as good. On the inside of the filler cap, however, there was indeed some ”mustard” (yellowish sludge), perhaps half a teaspoon of the stuff, absolutely no more. That set the HGF alarm bells off in my wallet, but then again, I understand that there could be other reasons for such stuff to build up over time (clasping at straws here...) And shouldn’t there be more, and shouldn’t there be sludge elsewhere too, in case of a HGF? I’ve checked all over the engine for coolant residue, but the results were inconclusive. However, I did notice that one copperish-looking pipe (bear with me pls for not knowing all the exact technical terms here) that goes across the engine below it at the front, and which is connected to the hose leading down from the expansion tank, was greenish. Is that even an original part? Why put a piece of copper pipe into a hose-based cooling system? Won’t that cause corrosion from aluminium parts? There’s no misfiring, and I can see no white smoke from the tailpipe when driving, although I do tend to sit at the front of the car when driving, so visibility of the exhaust is somewhat limited... Grateful for any help or comment!