V6 cranking but not starting - run out of ideas!

[rita]

Silly question maybe but is the rotor arm turning when you crank the motor?

Its not a silly question, no turn it no go .

[nth]

Yes go to the start and then scroll right, the entire manual is in there.

The X-nn connectors are all at the rear of the manual before the index.

OK so X-35 is a 12 way connector? And the wires from the crank sensor are blue & Green?
I still can work out how you know which terminals the crank sensor wiring goes through on X-35?

[Albatros]

Silly question maybe but is the rotor arm turning when you crank the motor?

An excellent question Bongolia and no it does not move! Looks like it is the timing belt after all . I feel a right chump. My fault for not checking properly right at the start. Time I handed it over to some professionals. Is there anything I should consider changing at the same time? I notice a lot of places sell pulleys or seals with the belts.

Thank you Bongolia and everyone else who has helped, I appreciate all the advice I've had.

[Albatros]

Yes go to the start and then scroll right, the entire manual is in there.

The X-nn connectors are all at the rear of the manual before the index.

OK so X-35 is a 12 way connector? And the wires from the crank sensor are blue & Green?
I still can work out how you know which terminals the crank sensor wiring goes through on X-35?

I just followed the blue and green wires to the terminals. Fortunately there are no other blue or green wires running through the connector.

[rita]

You should be able to check if the camshafts are turning , if they are its a possibility that the distributor drive /dog has gone , you might be able to check the drive by trying to turn the rotor arm.

[willow2u]

Are the v6 engines interference type

[g8dhe]

Non-interference, but some one did measure the gap and its very fine indeed! I believe Allan has also seen some damaged engines but I'm also advised that dropped valves can cause a similar problem .... but I'm no engine mechanic!

[Bongolia]

Bugger!
Realistically what you would change when doing the belt depends on the engines pre belt failure condition i.e. cam seals etc.and how long you want to keep it. As a rule of thumb you would change anything crucial that rotates and is driven directly by that belt. Ideally and if the condition warranted it then any thing suspect or near the end of its useful life removed during the belt fit would be changed.

[JulesMartin]

If the engine is turning over easily at the moment then I'd suspect that the belt has just snapped as they do. Out of interest I wonder what the mileage is on your Bongo as I believe the usual lifetime of a cambelt is <>80,000 miles. Do you have any service history to say if it has been changed? In my experience with other engines if a valve drops the engine seizes instantly and snaps the belt but will not turn over afterwards or if it does you can hear distinct knock that would not have been there before. Does the engine have an oil leak at the front as this will dramatically shorten the life of a belt. In the past with other engines I've replaced the belt and got the engine started to see if any further damage has been done as these engines are apparently border line valve safe. if it starts up ok then consider changing oil seals, belts etc whilst you have the engine stripped down. if it has done internal damage then a leaky oil seal will, sadly be the least of your worries.

[nth]

Can you see any of the camshafts through the oil filler cap hole on this engine to confirm that they are not turning? Just because the rotor arm isn't turning doesn't definitely mean the timing belt has broken. As said above there is always the possibility that the drive dog on the distributor has sheared/broken. I have never worked on this engine so don't know the setup but some engines have a plastic drive dog.
That good news though that this is a non interference engine, would never have thought it

[Albatros]

I had a major oil leak at the end of 2016 and as a result the engine came out. I was told, and paid for, all seals gaskets and belts to be replaced. So if it is the cam belt then it has only done about 25k miles. However, the garage that did the work did not put it back together properly - something about one of the cam belt pulleys (I think) being put back on the wrong way around (apparently an easy mistake to make) so the car wouldn't start. It was sorted out eventually (following a telephone conversation I had with someone at mazdabongo.com that I relayed to the mechanic) but I have wondered ever since what else might not have been done properly.

Currently there is no sign of any oil leaks and no worrying noises occurred when it broke down (apart from the engine stalling) or when it cranks. It has now been towed and is in the hands of a local garage. Unfortunately there are no known Bongo specialists in the area but the owner of this garage does own a V6 Bongo so with any luck he has done plenty of work on it and knows it inside out!

Thanks everyone, this site has proven to be such a great resource. I'd be (even more) lost without it.

[Bongolia]

Fingers crossed but it sounds as though its in safe hands now.

[windywatson]

If replacing the cambelt on the V6 you need to be changing the following to ensure future reliabilty & trouble free motoring.
All cam & crank seals as the V6 is known to suffer from these becoming leaky. All cambelt tensioners & the weater pump. It is such a big job & as some coolant hoses have to be disconnected it makes sensed to do the water pump. Remember none of these vehicle are young in years.
Also make sure that the garage are well informed about the correct way to bleed the coolant system. Wouldn't want to do any damage due to air locks & overheating afterwards.

All the best with the work.

[Albatros]

Thought I'd post an update... the garage replaced the timing belt but couldn't get any movement from the engine. On closer inspection they could see that 2 of the valves were damaged but tell me they cannot be sure about any more damage without carrying out extensive work. I've been advised that at this point they could rebuild the engine but I should expect that more damage could be uncovered. I've been quoted £2.5k-£4k for a full engine rebuild depending on what needs replacing. Based on this, the garage has recommended that I look for a refurbished engine instead .

Sad news for my Bongo. I expected to get a few more years out of her. I've no idea what value she has in her current state but I should imagine that even with a £4k bill I will get more if she runs.

I've looked on ebay and there are a few v6 engines on sale, some claiming to be refurbed, ranging from £800 for a unit to £1750 installed. What do people think - is a replacement unit a sensible move? If so, any tips on what I should be looking for or what questions I should be asking? Of course buying a used engine comes with plenty of risk so I appreciate that there is no way I can be sure that I'll be getting something of quality.

The engine that is damaged hadn't even done 100k miles and the belt only 25k. But it is what it is!

I'm so glad this forum exists. I'd be so lost without it! Thanks again to everyone who has given any time to asking my questions.

[Allans]

What do people think - is a replacement unit a sensible move? If so, any tips on what I should be looking for or what questions I should be asking? Of course buying a used engine comes with plenty of risk so I appreciate that there is no way I can be sure that I'll be getting something of quality.

I've both replaced and rebuilt V6 engines. You don't know exactly what's needed until you strip it down. That's why a garage can only estimate the cost.

The parts for the rebuild can take quite a while to arrive (depends what's needed) and be pretty expensive.

Replacement with a decent used engine is usually cheaper and can be quicker.

The trouble is, if you buy it and its faulty, the engine supplier can blame the garage. And obviously the garage blames the engine supplier.

So its easier if your garage will source the part for you.

If you buy a used one, look for one with a warranty.