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Old 13th February 2015, 10:06   #1
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Default MG ZT-T+ 120 (F/Lift - Manual) Coolant Temp. reaching 105°C

1. In ambient temperatures of +5° to +15°C, recently the coolant temperature has been reaching 105°C.
2. 'Hans' temp. gauge fitted.
3. 'Gerry T' fitted
4. Coolant level is below the Min. mark when cold, topped up with about 250ml then is sitting at 'MAX' (bottom of fins.)
5. Gold resistor fitted 18 months ago.
6. Fan Slow Speed checked using the suggested method.
7. Indicated temp. reaches 97°C in about 2 miles from start-up.
8. Long trips (c100 miles)- indicated temp. remains at about 97°C.
9. Indicated temp. rises to over 100°C on steeper hills, in 4th or 5th. gear, but returns to 'normal' on the flat.
10. I have checked all hose connections and around the thermostat housing for any signs of leaks, none found.

Vehicle is one of the last ones built and I have had it from new, just under 50,000 miles on the clock and has been the most reliable motor that I have had. (Coolant temperature has never been over 100°C that I have noticed)

I am planning to drive back to the U.K. in a few weeks - some 1500 miles each way, do you think that I might be heading for trouble with the above conditions?)
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Old 13th February 2015, 10:32   #2
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No that sounds about right to me
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Old 13th February 2015, 11:03   #3
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The temperatures are normal, but regular topping up of coolant indicates a leak. Leaks in a 1.8 are a very bad thing and unchecked may send the temperature rather higher than 105C. That can send you in HGF territory.

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Old 13th February 2015, 16:52   #4
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Temperatures seem OK to me too. The common culprits for the leaks on the 1.8 K Series are:
Coolant Cap O Rings
K Series Inlet Manifold Gasket
K Series Thermostat Seals
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Old 13th February 2015, 16:57   #5
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When you say 'reaching 105c' is that idling in traffic or on the move? Personally I think your temperatures are a bit too high for a normally aspirated 1.8. It should run around 88-92deg under normal conditions. When reaching 105 I assume the low speed fan is cutting in normally and the temperature rapidly dropping to the low to mid 90's?

Both my turbo 1.8's never reached 100deg when under power even in hot weather, and I'm sure the NA 1.8 should be a tad lower.

Last edited by vindaloo; 13th February 2015 at 17:00..
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Old 13th February 2015, 17:02   #6
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I would double check any hose connection where EM clip has been replaced with a jubilee style one, with older hose sets they are prone to small leaks, some of this type of clamps do not grip the same in a complete 'circle' and can also cut into older hoses, take more care when checking where a leak can drip onto a hot surface and evaporate leaving almost no trace.
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Old 13th February 2015, 18:37   #7
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Quote:
Originally Posted by vindaloo View Post
Personally I think your temperatures are a bit too high for a normally aspirated 1.8. It should run around 88-92deg under normal conditions. When reaching 105 I assume the low speed fan is cutting in normally and the temperature rapidly dropping to the low to mid 90's?


Martin, can you confirm that your radiator fan is running when 105°C is reached?

You may have a lazy thermostat/PRT.

Simon
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Old 14th February 2015, 10:15   #8
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Quote:
Originally Posted by chipsceola View Post
I would double check any hose connection where EM clip has been replaced with a jubilee style one, with older hose sets they are prone to small leaks, some of this type of clamps do not grip the same in a complete 'circle' and can also cut into older hoses, take more care when checking where a leak can drip onto a hot surface and evaporate leaving almost no trace.
No signs of a water leak to atmosphere seen, all clamps appear to be 'sound' and the jubilee (ex-Concorde!)clips that I used to fit the Gerry-T also appear to be good. Tightened as a matter of course but no 'slack'.
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Old 14th February 2015, 10:23   #9
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Quote:
Originally Posted by SD1too View Post


Martin, can you confirm that your radiator fan is running when 105°C is reached?

You may have a lazy thermostat/PRT.

Simon
Just been to my Motor mechanic to book the car in for its 2 year 'MoT', and service. We discussed at length the conditions that I have listed and they have suggested
a. Radiator Cap Seal and
b. Thermostat
c. Water Pump.
But they will have a look when they get the car in on Wednesday next... Meanwhile, they have given me a bottle of Wurth - Radiator Cleaner - 250ml - Radiator Flush to put in when the rad. cools down. They will drain and refill with coolant as per the spec. that Jules recommends, when they have the car next week.

Last edited by Time Searcher; 14th February 2015 at 10:31.. Reason: ommited details
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Old 14th February 2015, 10:29   #10
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Quote:
Originally Posted by SD1too View Post


Martin, can you confirm that your radiator fan is running when 105°C is reached?

You may have a lazy thermostat/PRT.

Simon
I was not able to get the temperature up to 105°C this morning, (max. 102° when parked up before going out) but it did fluctuate when under load, between 92 and 102. The rad. fan did not cut in on the 10 mile trip to the garage and back.
See above post regarding Thermostat ↑
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