Ford V6 Duratec 2.5

[Heat1475]

im contemplating the purchase of a V6 Duratec 2.5, does anyone know if it has timing belts or chains. Are there any common faults that i should be looking for.

[Marty V8]

I've had two Mondeo V6's a Mk1 24V and my current car an ST24. The engines are nice and smooth. They have two individual timing chains run off the crank, one chain per cylinder bank, and each chain drives two cams, so no need to muck about with cam belts.

My Mk1 had the water pump problem. What happened was that the plastic impellor cracked around its base and then didnt turn at the same speed as the shaft it was pressed on to. This overheated the motor in a very short time. I ended up taking the heads off to see if they had warped, but they were fine.

My father had a look at the water pump (he's worked with turbines all his life) and commented that his pond pump was of better construction.

I went on to do 110,000 miles in it and part ex'd it for my ST24. The sales manager used the MK1 24V as a hack for the next two years, and the last I heard of it it had 130,000 miles on it and was still going well.

I think the later Mk2's had a revised water pump, but I could be wrong. My ST24 has 85000 miles on it and is still going strong.

If urban myth is to be believed, its supposed to be a hacked down V12 Aston Martin engine, but how true that is I dont know. I do know that Noble used it in highly modified turbo form (over 300bhp) in their original M12, and the later ST220 3 litre motor in their next car as well.

having had two V6 Mondy's, I'd certainly have another car with this engine in it.

Edited by Marty V8 on Saturday 24th April 20:08

[Spitfire2]

2.5V6 in my old Cougar went to 140,000 miles with no engine problems whatsoever.

Only issues I had in engine bay was with the Air Conditioning Compressor and also with the device on the front of engine which activates the 2nd set of valves when you pass 3200rpm (it runs as a 12 valve engine below that - gives a nice kick of acceleration when you pass that RPM....)

Was a tad on the thirsty side tho.

[Marty V8]

Spitfire2 said:

2.5V6 in my old Cougar went to 140,000 miles with no engine problems whatsoever.

Only issues I had in engine bay was with the Air Conditioning Compressor and also with the device on the front of engine which activates the 2nd set of valves when you pass 3200rpm (it runs as a 12 valve engine below that - gives a nice kick of acceleration when you pass that RPM....)

Was a tad on the thirsty side tho.

I'd forgotten about the secondary butterflies. This was a vacuum (I think) activated valve on the Mk1 but on the Mk2 ST24 its an electric motor which controls the secondaries and this is sat on top of one of the cylinder banks. I managed to re-solder one of the connections on the circuit board which had formed a dry joint.


You're right about the thirst as well.

[Kitchski]

On the v6 economy front, i've an st200 which rarely betters 22mpg. Seems to run ok, but secondaries box needs an overhaul and i've done the throttle hang mod....can either of these affect economy?

[anonymous-user]

Economy will go to tit if the IMRC is playing up. The 2.5 will easily do 28MPG, with 34+ on a run at sensible speeds.

[Marty V8]

Dave_ST220 said:

Economy will go to tit if the IMRC is playing up. The 2.5 will easily do 28MPG, with 34+ on a run at sensible speeds.

I'll have to swap my ST24 for an ST220 then as I have never got these figures. I once got 28 mpg on a long run - Co. Durham to Penzance, but nothing like that normally.

[S. Gonzales Esq.]

January: http://pistonheads.com/gassing/topic.asp?h=0&f...

February: http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[anonymous-user]

Marty V8 said:

Dave_ST220 said:

Economy will go to tit if the IMRC is playing up. The 2.5 will easily do 28MPG, with 34+ on a run at sensible speeds.

I'll have to swap my ST24 for an ST220 then as I have never got these figures. I once got 28 mpg on a long run - Co. Durham to Penzance, but nothing like that normally.

I got 29MPG out of the 220 without even trying, if you stuck to 70MPH and drove like a poof it would do 35 but you don't buy a 3l V6 to do that do you?! Sounds like your ST24 has something wrong(or you enjoy it!) as my old Mk1 V6 returns 25MPG with town driving & 28 with mixed, on a run i got 35MPG.

[Dimski]

Marty V8 said:

Dave_ST220 said:

Economy will go to tit if the IMRC is playing up. The 2.5 will easily do 28MPG, with 34+ on a run at sensible speeds.

I'll have to swap my ST24 for an ST220 then as I have never got these figures. I once got 28 mpg on a long run - Co. Durham to Penzance, but nothing like that normally.

Your economy seems a little low there Marty. Is it an Auto?

I spent a year with a 2.5 V6 Ghia X, and it rarely dropped below 33mpg, mainly on motorways. I did find that I would often set the cruise at 70mph, as it was such a comfortable, quiet, relaxing drive at those speeds.

Two best figures were 35.2, at 80-85mph on a drive from Manchester to Zermatt, and 40 mpg when traveling at 50mph on a motorway while letting a friend catch me up who was over 1 hour behind.

Worst was 23mpg, 4 up, boot full to bursting, from the Italian border to Calais. Mind you, I wouldn't risk those speeds again!

[Zad]

Trundling back on cruise control from Bradford on the M62 through the 50MPH SPECS cameras, the 2.5 I was in yesterday was reporting an average 42mpg. That did drop to low 30s in 70mph fast/slow 'lumpy' traffic, but it does indicate what you should be able to get.

[Marty V8]

Dave_ST220 said:

I got 29MPG out of the 220 without even trying, if you stuck to 70MPH and drove like a poof it would do 35 but you don't buy a 3l V6 to do that do you?! Sounds like your ST24 has something wrong(or you enjoy it!) as my old Mk1 V6 returns 25MPG with town driving & 28 with mixed, on a run i got 35MPG.

Please dont think I'm whining about the fuel economy because I'm not - far from it. I do like driving the old beastie, although the recent rash of performance oil burners has almost made it pointless. I drive it in lets just say, a spirited fashion but only for the last 75000 miles. In all this time the mpg has never been brill and neither was it in my old Mk1 24v Mondy.

Drive it like a poof? you must be joking.

I started looking at ST220's a while ago to replace my ST24 but was put off by the scare stories of being nailed for £400/year road tax. Isnt it now the case that it only applied to cars built after 2006?


Cheers

Marty

[Kitchski]

Dave_ST220 said:

Economy will go to tit if the IMRC is playing up. The 2.5 will easily do 28MPG, with 34+ on a run at sensible speeds.

Interesting, i assumed the imrc box would if any thing improve the economy its restricting it to 12 valves at times, less airflow, less fuel etc? I'd be chuffed if it is ruining it as relocating the box is on my list of things to sort! its an st200, are they more thirsty than the other 2.5's on average?

[anonymous-user]

IMRC failure=it will run on 18 valves 220 VED IS over £400 if built after March 2006 IIRC?? Worth it mind The 200's will of course have worse economy but by how much i do not know, shouldn't think much considering what the heavier more powerfull 3L returns!!

[Kitchski]

18 valves? I might need to do some research here! what actually fails on it then?

[Marty V8]

Kitchski said:

18 valves? I might need to do some research here! what actually fails on it then?

Its not actually the valves that fail. There is an upper and lower intake manifold on the V6 motors. The upper manifold is the nice black smooth part that is sat on top of the engine, if you have an ST200 (or an ST24 with a throttle body mod and an ST200 Upper Inlet manfold ) The ST24 or 24V Mondeo version is the grey rough version.

Beneath this upper inlet manifold, is the lower inlet manifold. This has two sets of butterflies per cylinder set into it. Below 3250rpm only one set of these butterflies open and close with the throttle (I think they might all open at wide open throttle as well but am not 100% sure). Above 3250rpm an electric motor which is sat on top of one of the banks of cylinders pulls open the second set of butterflies so that all 12 are now open and greedily sucking in air.

If the V6 Mondy seems to be holding back and is generally slow on acceleration, its failure of this electric box of tricks that is the usual culprit. Its not a difficult fix either. This is for the Mk2 Mondeo. The Mk1 Mondeo also suffers the same syptoms and its due to the same issue with the butterflies not opening. The actuator is a diferent type though and I seem to recall that its vacuum operated rather than electrically operated.

There is an awful lot of information about this and other Mondeo issues on the Mondeo Enthusiasts Group website.

Cheers

Marty

Edited by Marty V8 on Wednesday 28th April 18:06

[Marty V8]

Going back to the previous post about fuel economy, maybe I should have remembered that my Mondy isnt err, standard either, so not much surprise that its not the most economic car on the planet. I think its early onset alzheimers so apologies

I swapped the upper inlet manifold for an ST200 version, and also got hold of an ST200 throttle body which is larger than the ST24 version. It sucks in via a larger diameter air tube on to which is nailed an Escort Cosworth Cone shaped air filter.

I also modified the exhaust several years ago when it started to rot. Instead of being piped under the car to the passenger side silencer and then out of the drivers side, I have done away with the pipe to the passenger side silencer. So now it comes from the centre cat to a silencer on the drivers side, and thats it.

However, even before I started nailing bits to it, my ST24 never got the economy that others have got from theirs.

Cheers

Marty

Edited by Marty V8 on Wednesday 28th April 18:59

[anonymous-user]

I doubt you have the ST220 versions as they are oval ports & your car will have round ports in the head. My V6 also has the ST200 LIM & UIM & TB, when it had the modded Y pipe on econonomy was even better!!

[Marty V8]

Dave_ST220 said:

I doubt you have the ST220 versions as they are oval ports & your car will have round ports in the head. My V6 also has the ST200 LIM & UIM & TB, when it had the modded Y pipe on econonomy was even better!!

Well spotted you are absolutely correct - I told you it was early onset Alzheimers - wot I really meant was ST200 versions - have now changed the previous post (from ST220 to ST200)to confuse people even more. I blame it on the aliens I'll get me coat - again

Edited by Marty V8 on Wednesday 28th April 19:00

[anonymous-user]

Have you washed the filter recently & cleaned the MAF? That can make it over fuel, also, what colour injectors are you running? If the ST200 ones are still in (green) the you are chucking fuel down there & losing power!