V6 overheating

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haydn callow
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V6 overheating

Post by haydn callow » Tue Sep 06, 2011 11:57 am

Now there are more V6's on the road, reports are coming in of overheating and head gasket problems..
The latest (on the "other" forum), is one that lost coolant and was incorrectly bled at the roadside. This caused "hopefully" just head gasket failure.
Not heard of damage to cylinder heads yet so hopefully with the V6 just the gasket goes..

I know of 3 V6's that are off the road at the moment co's of split rad's, incorrect bleeding and "popped" hoses.....It would seem that the same issues are there (age related) but hopefully the damage caused by overheating is not as bad.

I personally haven't bled a V6 yet.......I have seen it done and following the "normal" instructions should produce the required result........as the V6 runs a bit cooler it may take longer to get the stat open.
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Re: V6 overheating

Post by cheffy34 » Tue Sep 06, 2011 3:29 pm

I did say years ago it was just a matter of time :!: and we would see more issues as more come into the country :D i'v bled mine a few times now just the same, as with all over heats IMHO it is how quick you catch it as with most cars you boil them you cook the heads, at the end of the day it has the same length of pipes leading to the rear con as the diesal and it will suffer the same issues, i would be surprised if it just killed gaskets it surely would depend on how bad you cook it


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Re: V6 overheating

Post by Doone » Tue Sep 06, 2011 4:25 pm

Not heard of damage to cylinder heads yet so hopefully with the V6 just the gasket goes...
Speaking from experience (well, my husbands experience :wink: ) V6 heads and/or gaskets can fail after they have overheated, depending on how serious the overheating episode was.
He's not yet seen as many as he's seen diesels, and as there are not yet as many around, it's not possible to compare 'failure rate' with any degree of accuracy.
The reason for the failure has so far been the same as on the on the diesel Bongo - and most other vehicles - lack of maintenance, coolant loss, or component failure.
Allan's closed. We recommend PGS (Plymouth Garage Services) or Mayflower Auto Services in Plymouth.
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Re: V6 overheating

Post by haydn callow » Tue Sep 06, 2011 4:45 pm

Thanks for that Lorna....do you know if V6 heads are obtainable ?....do both heads tend to go ? or does it involve a replacement engine ??
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Re: V6 overheating

Post by Doone » Tue Sep 06, 2011 4:48 pm

He has V6 heads, so they must be obtainable, as are all other parts needed to do the job. :) (The heads look quite small and neat compared to the diesel ones.) One or both heads can fail and you don't usually need to replace the engine (block) if they fail.
Allan's closed. We recommend PGS (Plymouth Garage Services) or Mayflower Auto Services in Plymouth.
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Re: V6 overheating

Post by Cloughy » Wed Sep 07, 2011 9:32 am

Hi,

I've had two near overheating episodes (98 V6 123000KM), but was saved by gadgets both times.
1. Stuck thermostat - this also brought to light a problem with the rad fans never switching in, I fitted an iAlert, and later a relay was fitted at Wheelquick to switch the fans in automatically from the iAlert's switch signal. I can now set the iAlert to switch the fans in at a given temp or use a separate manual switch (fitted by Adrian in Bury) if I get paranoid.
Mason Alarm saved me when the problem first started. =D>
2. Leaking radiator - seeping out at the top edge where the metal joins the plastic, I was on holiday, but the local garage in the lakes got a replacement rad by the next day. Insurance/AA cover through Safeguard meant I got a free car for two days until it was fixed. Wheelquick checked it and found the Lakes garage had bled it successfully.
Low coolant Alarm Saved me this time =D>
3. Also had a slightly loose hose which lost me about 200ml of coolant per 1/4. Finally discovered it myself and a garage tightened the clip and no further problems. Again LCA kept me aware with the occasion and increasing beeps.

I wonder if people should routinely replace the thermostat?

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Re: V6 overheating

Post by haydn callow » Wed Sep 07, 2011 9:41 am

Unfortunatly the i-alert temp gauge alarm is no longer available.....can you let me know the amp rating of the relay Wheelquick fitted to cause the i-alert to switch the fans....

The recently introduced 3rd generation Low Coolant Alarm has the "extra" bit of power available to switch a small relay.

I will make the details available shortly.
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Re: V6 overheating

Post by jaylee » Wed Sep 07, 2011 9:58 am

Hey up,

Just wondering.. Is a V6 stat designed/set to open fully at a lower temperature as opposed to a diesel?

Or is a diesel & petrol variant (2L or V6) stat the same..??

If yes to question one & no to question two, is it possible to install the wrong type stat causing issue with the V6?? :-k

Just a thought!
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Re: V6 overheating

Post by Cloughy » Wed Sep 07, 2011 11:55 am

[quote="haydn callow"]Unfortunatly the i-alert temp gauge alarm is no longer available.....can you let me know the amp rating of the relay Wheelquick fitted to cause the i-alert to switch the fans....

I think the extra relay was put in to change the polarity of the switch signal from the iAlert. This then went to another relay which I think was the factory relay that operates the fan normally, which in my case never got switched (apparently).
[If that doesn't make sense, it's because I don't actually know what I'm taking about :? ]

I'll try and find the extra relay, under the steering column and post the details tonight. It is working well.

What would the normal running temp for the V6 be?
I have the sensor on the side of the block, it was reading 88 on the motorway and going up to 94 when I was pushing on a bit harder. I was wondering where what temps to set the Alarm on, fan on and fan off triggers. The mason alarm seemed to pip around 95-8 when I stopped for fuel, but stopped as soon as I set off again.

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Ron Miel
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Re: V6 overheating

Post by Ron Miel » Wed Sep 07, 2011 12:58 pm

haydn callow wrote:....It would seem that the same issues are there (age related) but hopefully the damage caused by overheating is not as bad.

I personally haven't bled a V6 yet.......I have seen it done and following the "normal" instructions should produce the required result.........
It bled fine, using the "Mazda-method" on the one occasion I did it, so far.

Agree with cheffy34 in the next post though that ageing V6s must have the same urge as 2.5TDs, to dump coolant through worn out pipes, hoses, clips, rads, etc. - but Steve Widdowson's research showed a particular vulnerability to head cracking in the diesel Bongo, due to a thin metal area top/front of the head, and with luck the V6 doesn't have that to contend with..

Hopefully, even as now-aging V6s do spawn an increasing number of overheats, the resulting head failure rate will therefore be lower. A shameless plug for you here, Haydn: fit LCA/temp monitors, and they definitely will be.

The LCA saved mine three years ago, when it precipitately dumped a lot of coolant after a (cambelt change job) poorly refitted top hose gave way, and the TM2 showed only a small block temperature rise, thanks to the immediate LCA warning and a rapid stop.
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Re: V6 overheating

Post by haydn callow » Wed Sep 07, 2011 1:02 pm

My actual coolant temp (sensor inside the top hose where it exits the cylinder head) tops out at about 78C and during "normal" running averages about 66C.

My cooling system is in "as new" condition, having had chemical flush x 2, New coolant x 2 and a new rad and stat.

The only time my stat opens is when I restart after a stop on a long journey.. Temp 85C
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Re: V6 overheating

Post by haydn callow » Wed Sep 07, 2011 1:08 pm

Ron,
Did you manage to get the Stat open (bottom hose HOT) whilst bleeding using the "Mazda" method of bleeding and did you notice a significant drop in coolant level the next day when cold, other than what you would expect from coolant contraction (about half a inch) ??
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Re: V6 overheating

Post by Cloughy » Wed Sep 07, 2011 1:10 pm

haydn callow wrote:My actual coolant temp (sensor inside the top hose where it exits the cylinder head) tops out at about 78C and during "normal" running averages about 66C.

My cooling system is in "as new" condition, having had chemical flush x 2, New coolant x 2 and a new rad and stat.

The only time my stat opens is when I restart after a stop on a long journey.. Temp 85C
That's interesting, those are almost exactly readings I had when the sensor was on the head on passengers side. I moved it down when the relay was added at Wheelquick.

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Re: V6 overheating

Post by Ron Miel » Wed Sep 07, 2011 1:26 pm

It was a couple of years ago, so I'm a bit hazy, but I think the next day's coolant drop was more than just normal contraction, and it needed a bit of a top up - but it certainly didn't get down anywhere near the LCA's bottom terminal. After that, no more top ups were needed. Yes, the thermostat opened during the bleed.

My TM2 sensor is surface mounted, on a bolt close to the top hose(s) outlet spigot, close to the Mazda temp gauge sensor. During normal running with airflow, as opposed to when bleeding with no airflow, it gives readings, ranging from about 78C to 83C, the latter either when stuck in traffic with little or no airflow, or when heavy laden and hill climbing..
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Re: V6 overheating

Post by Cloughy » Wed Sep 07, 2011 1:33 pm

My TM2 sensor is surface mounted, on a bolt close to the top hose(s) outlet spigot, close to the Mazda temp gauge sensor. During normal running with airflow, as opposed to when bleeding with no airflow, it gives readings, ranging from about 78C to 83C, the latter either when stuck in traffic with little or no airflow, or when heavy laden and hill climbing..
I'll move mine back to it's old head position, I think I have the wrong place now. The temp changes were more responsive before and I guess it's the head(s) I'm trying to protect!

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