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There has always been a long debate about thermostats and controled temperatures in Busso V6 engines and I have learned the hard way what is best for these engines. To spread the information to all I chose to post this info:
1. In a Busso the temperature scale has a line marked 50 degrees, a second unmarked line and a line at 90 degrees. The correct temp for your Busso is 90 degrees. The second unmarked line is 70 degrees. Not 80 degrees as some speculate. When your temp drops to 70 it is time to replace the stat.
2. Busso engines have hard cylinder liners. They only give in to serious abuse. Rings will fail before the liners do.
3. The Busso engine has 3 temperature senders: one for the engine temp gauge, one for the ecu and one for the overheating light.

What this all means:
1. If your temp drops to the second line (70 degrees) while cruising then replace the stat. It has already failed by this point. Other symptoms are long heating period (taking long to heat up to at least 70 degrees).
2. Engine liners may be strong but the rings let go easily with overheating. So not just compression, but oil comsumption increases in an engine with a worn stat. It will require new rings, besides the new stat and gaskets when the engine finally lets go.
3. Go by what the gauge tells you. If it is showing cold for along period and your diag equipment shows that the ecu is reading a higher temp, realise that this is NOT ok. The gauge temp is your guide. If it shows 95 degrees in traffic then your ecu will be reading a much higher temp and the light is sitting there waiting for 110 degrees before it turns on.

Note that under normal conditions when you turn the engine off, the engine fan will go off. If it doesn't then the ecu is reading above 95 degrees and you are at risk of overheating.

I have followed the suggestions of those on the site stating that since the stat fails open you are at no risk of losing an engine. I did, because of this. My stat was fully closed when removed. This comes as a surprise because it would read low for along time before showing 90 degrees. This already should have been a warning.

My rings were not replaced due to the fact that the engineers called them to be fine after compression tests to determine if the heads have blown and the leak was found to be between Cylinder 1 and 3. But I am now unsure about how long my engine will last before it needs new rings, which would be a waste of money if it would be found that my rings are shot 10000km after a head rebuild. I want to ask them to replace the rings as well but this will cost me abother R10k which I don't have.

So please, do yourself a favour, replace the stat at R500 before losing a good engine to hear-say stories. It WILL let go and cost you 20 times that to repair...

Cheers. Stay well over the festive season. :xmas:
 

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Good post. @Gausie if you read this...and you drive the GTA you'll notice its steady at between 70 and 90 on highway cruise...hook it up to the MES and you'll see the temps correlate with the gauge.

BUT...with that GTA, I've found that driving with the A/C on is an acceptable solution to force the 2nd fan to work when in traffic as it'll only start working at an ECU temp of 98 degrees...tested and confirmed with GTA guys in the GTA lounge. At this time that digital dash will show over 90 degrees and you'll freak out...just like I did. 2nd fan kicks in LATE(98degrees) and it happily runs back to 90 degrees ECU temp and digital gauge.

Now, as Ian points out...hearsay(I won't say its hearsay, more so guys have been pedantic and based on what they see decide to replace the thermostat as the >90 degrees on the digital gauge freaks everyone out) this has been discussed at length in the GTA lounge.

My verdict as previous owner of that GTA...replace the thermo ASAP.

But here's Ian again with his cheap parts...R500?:paranoid: Where bra? I got quote it was like R780 I think...still cheap, but worth the do. Its like the cambelts...just replace the Thermo :thumbup:
 

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On numerous GTA's and 2.5's we have replaced the 'stats (With original Alfa stats mind you) only to get the same "cool running" situation as with the old 'stats. So either they make a lot of 'stats out of spec, too many are duds, or the overall design is not as good as it should be.
 

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This is why I replaced mine ASAP. Mine still drops to 75 or so in highway cruising conditions.
 

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My GT is nearly due for it's cambelt service, but I'm doing the full service in January. Although it's only done 28k km since March 2012, I would prefer to leave nothing to chance. The change in thermostat was a contemplation, but now I'll have it changed as well, when I have the cambelt service.

Thanks for the good info above!
 

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Yes I think everyone I know has replaced the thermostat at some point in their Busso
Mine got stuck in the open position in winter and once temp around 50 the dam fan came on in high speed! Making it worse
Hopefully new owner does not have same problem
 

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Yes I think everyone I know has replaced the thermostat at some point in their Busso
Mine got stuck in the open position in winter and once temp around 50 the dam fan came on in high speed! Making it worse
Hopefully new owner does not have same problem
 

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I also found that a new thermostats was just as lazy to get up to 90C as older ones(due to large bypass?), but it went there. If it doesn't the stat is stuck open.

Before you change the stat, try adding a second liter of a good quality antifreeze (there should be antifreeze in the engine) and use the car for a week or two. I found that this freed the stat up. My assumption is that the (stainless)steel pin in the stat rust or get a layer of grit on it, which the lubricant in the anti freeze loosen. If this doesn't help, replace the stat.

Why is this important? The wet(loose) sleeves in the buso expand much more between cold and hot temperatures, than say an engine with a cast iron block. This is due to the cast iron block staying cold on the outside, inhibiting the expansion on the bores inside. Now running clearance for the pistons to sleeves is correct around 80 - 90C, meaning the smaller clearance with a cold engine will wear the rings down prematurely. below 70C will be critical. So do not rev the engine before the temp pass 70C.
 

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Hi

Thanks for some very useful information! Does this apply to the cf2 3L V6 24v in my 1998 gtv?

I have an intermittent engine temp fault , when warmed up the gauge goes to the second unmarked line after 50c. Occasionally the fan will kick in too. I've removed the sensor and tested the resistance with a multimeter and it seemed ok.

I think i will have to replace the thermostat. When I start the engine and hold my hand on the pipe it gets warm gradually as if the stat is stuck open. So you are saying that the runnin temperature should be around 90C?

Thanks
 

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Hi

Thanks for some very useful information! Does this apply to the cf2 3L V6 24v in my 1998 gtv?

I have an intermittent engine temp fault , when warmed up the gauge goes to the second unmarked line after 50c. Occasionally the fan will kick in too. I've removed the sensor and tested the resistance with a multimeter and it seemed ok.

I think i will have to replace the thermostat. When I start the engine and hold my hand on the pipe it gets warm gradually as if the stat is stuck open. So you are saying that the runnin temperature should be around 90C?

Thanks
This goes for all engines, but is more important with Nords and Busos due to wet sleeves. 90C is the target temp in your GTV. The fan is controlled from the radiator switch and the gauge from the sensor by the termostat. Yes the the pipe to the radiator should only heat up after the engine got to 70C and the thermostat open.
 

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Ian, I am not questioning your advice at all but I find it unlikely the engine can sit at 90 degrees all the time, even when sitting at 140 km/h on the highway. There is simply too much wind cooling for it to sit at that temperature constantly.

Mine, if I sit in traffic it sits at 90 degrees, switch the air con on and it runs cooler than that. Out on the highway if its a very hot day it sits between 70 and 90.

Nevertheless when the belt is changed again will ask Giorgio to change the thermostat as a precaution.
 

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Mine used to do that on highways in summer fluctuate between 70 and 90
However in winter early in the morning it would drop to 50
Once I changed the thermostat it sat on 90 all the time irrespective of traffic conditions
 

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I think I'll change the stat and temp sensor as a precaution just for peace of mind. Which is the best online parts store to buy these from? I'm also after some suspension bits too.
 

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The issue with fluctuating temperatures seems unique to the V6's. I am yet to see a Twinnie with a good thermostat going below 90 degrees when driving. Maybe, on a damned cold day, it may drop just below 90 degrees for a few seconds, but it is dead on 90 degrees most of the time.
 

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When mine gets to 90 the fan comes on, so in essence if one is sitting at 90 all the time the fan would be running all the time...

I also think one needs to make a distinction between water temperature and actual block temp.
 

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Having read this post this morning I carefully monitored my temps while driving around today in my 156 GTA. On the highway at 120 ish the temps sit just above 70 on the gauge with aircon on. If I drop down to 80-90kmh then the temps rise nearer 90. Town speeds I'm on or slightly over 90.

I track my car quite often (Zwartkops mainly) and after 4-5 laps I'm just over the 110 marker on the gauge. If I run the heater on Max then its just below the 110 marker. Never seen a warning light. I have seen coolant being expelled from the cap on the expansion tank (assumed from excess pressure over the caps limit).

I had the stat and radiator changed in Jan. Might I have a faulty stat? Or possible bigger problems? Or do GTAs just run hot on track and I should limit my sessions to 2-3 laps? (Which I've been doing as a precaution).
 

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I've found alfaworkshop to have a good range of parts and reasonable prices, does anyone use them? shop4parts doesn't have some things like rear bump stops, inner cv boot etc
 
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