Hot Start Issues for T25 1.6TD

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TomLeighton
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Hot Start Issues for T25 1.6TD

Post by TomLeighton »

Hi everyone,

I hope you don't mind me picking your brains.

I have a T25 Turbo Diesel 1.6l

Last year we had a few issues, to say the least.

The main problem is that it won't start when the engine is hot and we were losing oil all the time. I had to top up the engine every journey.

This all started last year when I managed to break the radiator. Prior to that I had a new alternator fitted as the old one died but this was
1. At the beginning of 2019 I needed a new alternator as battery was not recharging properly.
2. In March we had a new radiator fitted, Definitely my fault. Filled up the overflow tank instead of the water reservoir! I only discovered this when the rubber hose from the reservoir blew up, and smoke came out of the radiator!

This also lead to:
3. A reconditioned diesel injector was fitted and theoretically the glow plugs have been tested and reset.
4. The crankshaft had a new seal.
5. The cam belt has been retimed.

I don’t know if 3 and 4 are connected to me blowing the radiator but very likely.

Since all this started, a separate mechanic noticed that the fuel enrichment cable/choke was broken and had been for many years. So in fact I've been driving with it on for 10 years or so and never realised as it still pulled out and in. This has now been repaired.

In the process of doing this, the first garage that did the work didn't get it right first time. Or second, or third. In fact I've taken it back about 8 times now. Every time I go back to them explaining that the van won’t start when hot and loses oil.

Thankfully not paying each time as it's under guarantee. I don’t really mind what it takes to repair it, however, I just want my van to work and I don't trust them to do it any more.

We were oil constantly. I think this was because the hoses that link the pistons / glow plugs were not fitted securely, and the last time we went in the mechanic said this meant air was getting into the engine and this may be the cause of the hot start issues. He has now secured the hoses.

However, I would have thought that air getting into the engine would make it bunny hop all over the place, and this wasn't happening.

I do get quite a bit of white smoke out of the engine when starting.

I have also read on this amazing forum that it could be an issue with the glow plug temperature sensor. I did check this, give the contacts a clean with sand paper and reattach it. Since then the glow light on the dashboard takes about 1 minute to turn off, as opposed to 10-15 seconds. Is that normal?

Since I cleaned the contacts it does seem that the engine will restart when hot but not every time.

Can this really be the only thing stopping an engine starting when hot? I'd be really happy if it is, but want to check before driving off into the sunset and straight into the arms of the RAC.

The hot start issue started around the time I had the alternator repaired, could the issue be with the alternator, not the cambelt or diesel injector?

Do I need to check the alternator power as well?

Any advice or ideas would be greatly appreciated. I’m no mechanic, but I don’t trust the ones we’ve been dealing with.

Thanks,

Tom.

RogerT
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Re: Hot Start Issues for T25 1.6TD

Post by RogerT »

Hi Tom
No answers for I’m afraid, but I hate to see a post such as this go I replied.

So, starting at the top

Hot starting problems - could you describe what happens when you try to start it when it (the engine, I’m assuming) is hot? As much detail as possible, and how hot? Stopped at the lights/stopped at the corner shop/stopped for lunch?

Losing oil - do you have a leak when sitting stationary? How many litres do you top up per 1000km (I seem to remember VW say 1 l per 1000km is at the top end of acceptable?)

You say blowing up the rad was your fault. Don’t be too hard on yourself. A sorted cooling system doesn’t need toppings up. The reservoir (with the cap on top) should be brim full. You should top up at the overflow tank(behind the number plate) to the max mark. Sounds like you had problems somewhere.

Smoke coming out of the rad?? Black/white/ or was it steam?

Rubber hose from the reservoir blew up - which one?

Fuel enrichment/choke is in fact a cable that changes the pump timing to aid cold starting. Called a cold start cable. Pull it out to start when cold, push in as soon as you can . Or if your van Is like mine and it’s banjaxed, fix the lever on the pump so that it’s always in the cold start position. The pump timing is only affected up to a certain (relatively low) rpm, so no effect when driving. Cold start without the cable pulled results in poor starting and copious smoke, really unpopular on a campsite :oops:

The hoses that link the pistons/glow plugs... I wonder if you’re referring to the fuel return hoses? That’s all i can imagine. Loops from injector to injector (which you might be confusing with the glow plugs? Injectors also have the metal fuel pipes going to them from the pump, glow plugs are to the right of them as you look at the engine). Not an expert but I don’t see that causing your oil usage. At all!

Air getting into the engine... I suspect you mechanic meant air in the fuel? I.e air bubbles getting into the fuel line before the pump. After the pump the fuel is at high pressure, so sprays out of any holes in the metal fuel pipes. The fuel return hoses are not under any significant pressure, as far as I know.

Could you tell us more about how it runs generally?

Hopefully someone more knowledgeable will be along shortly. By the way, it’s good you’re not paying for all these trips to the garage.
Have you ever seen an unhappy fool?

88 Transporter with hitop camper conversion, 1.6td.

Timburrows
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Re: Hot Start Issues for T25 1.6TD

Post by Timburrows »

You say the engine won’t start?do you mean turns over and doesn’t fire or when you turn the key nothing happens?

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mrhutch
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Re: Hot Start Issues for T25 1.6TD

Post by mrhutch »

Tom, fill in your rough location in your signature, there's loads of us on here that are au-fait with the joys of an IDI engine.
1981 Vanagon Westy Burning oil as fuel...  

jas915
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Re: Hot Start Issues for T25 1.6TD

Post by jas915 »

Does sound a few issues , but maybe simple to fix. I would definitely check the bleed off pipes between the injectors, any dampness / deisel smell then replace them. The braided type tubing lasts maybe a year, brickwerks don't sell it anymore but do have something more suitable. Last year my van wouldn't start and it was due to a leak from these pipes drawing in air. Replaced all good. Also I've have air getting in from the top of the fuel filter ( the thermo value bit) so maybe worth checking that and replace if old.
It won't be glow plug related if hot as they aren't really needed.

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TomLeighton
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Re: Hot Start Issues for T25 1.6TD

Post by TomLeighton »

Apologies for the radio silence,

At first I thought I was getting notifications when people replied but apparently not and thought no-one had any ideas.

Then last weekend we took the van out for another test run after the garage swore blind it was fixed. Just about a mile from the end of the M3 motorway after having driven for about 1 hour there was an almighty bang and clunk and the engine stopped working. We very luckily managed to free-wheel it to the junction and onto a bus stop near Twickenham.

We thought maybe the pump had stopped working. However, the new garage we have taken the van too have given us much worse news. The crank shaft sprocket was disconnected from the engine because the bolt had been sheered off. The pistons and valves have been damaged and we need an engine rebuild. The old garage had done some work on this and it looks like they didn't install the crankshaft pulley bolt correctly.

In my hunt for a new engine I came across AW Engineering. As soon as I mentioned the hot start issue he suggested that the sheered bolt and was a result of not fitting a new one when they adjusted the replaced the crankshaft seals and did the timing.
 I spoke to a very helpful man called Keith, the owner of the garage, who immediately said that the hot start issue is probably the same as the sheered crankshaft pulley bolt issue.
 Apologies if I'm speaking in layman's terms below, you probably all already know this, but I am learning a lot about crankshafts at the moment and this is how he explained it to me. Apparently the bolts should be replaced every time you remove or work on the crankshaft.The crankshaft is connected to a gear which over time if the bolt is not at the correct tension or is worn means...the keyway in the gear moves by about 5 degrees, which then means...the pump timing is out and hence...we couldn't start the engine when hot.

So long and short of it is, I have a very expensive heap of metal in a garage somewhere in Catford and we're looking for a reconditioned engine. Anyone got any other recommendations for companies that sell reconditioned engines other than AW Engineering?

By the way, we're based in Camberwell, SE London for the next time.

Thanks,

Tom.

 

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mrhutch
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Re: Hot Start Issues for T25 1.6TD

Post by mrhutch »

ahhh, the old crank bolt failure....

Don't worry, most of have been there!  VW introduced a "fix" for the sub standard bolt, but it is still a one time use I think.  

for ease look for a 1Y (1.9 non turbo) engine to swap in.  I usually have a few of these for sale, but at the moment I have nothing ready.

Or consider going GTi?
1981 Vanagon Westy Burning oil as fuel...  

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Re: Hot Start Issues for T25 1.6TD

Post by davidoft1 »

mrhutch wrote: 03 Jul 2020, 12:45 ahhh, the old crank bolt failure....

Don't worry, most of have been there!  VW introduced a "fix" for the sub standard bolt, but it is still a one time use I think.  

for ease look for a 1Y (1.9 non turbo) engine to swap in.  I usually have a few of these for sale, but at the moment I have nothing ready.

Or consider going GTi?


No need for Vw to come up with “a fix” people just reused a one time use stretch bolt , new bolt no issue, thing is you don’t need to undo it it do the belt , undo the 4 Allen keys , easy peasy

TomLeighton
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Re: Hot Start Issues for T25 1.6TD

Post by TomLeighton »

I think for ease I'm going to replace a like with like engine. It's quicker and cheaper and I've just spent £800 having the fuel injector restored so not getting rid of that.

The crankshaft needed to a new bolt as the crankshaft seals were replaced. But yes, it seems everyone knew apart from my garage and me knew you should always replace the bolt....

Tom

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