P38 engine problems and I don't know where to turn

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Warrington Paul

New Member
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Hi Guys and Girls,

I'm new to the forum and have a major problem with my 4.6 1998 P38. The left head gasket went and I used a mechanic to sort it, trouble is that he took so long to do the job he didn't know where all the pipes ended up going, so in his infinite wisdom he blocked a couple off and thought it would be ok. Now the plenum chamber is popping (only to be described as an empty oil drum sound with air being sucked in and out) Some people have said it's a valve or the other head but I'm sure it's just plumbed up wrong. It's got a Romero gas conversion on it. So what I'm asking is help in identifying where the pipes go, mainly the one from the left rocker cover to ???? and the water pipe from the bottom of the expansion tank and the valve on the left of the plenum cover. I'll add some pictures as soon as I can. Meanwhile if you could help I'd appreciate it. Thanks Paul
 
I've added 4 photos.

1 Are the pipes connected correctly?

2 On the plenum cover left hand side, what pipe goes here?

3 On the rocker cover left hand bank, what goes here? and does it connect to picture 2?

4 Hardened plastic water pipe, comes from the bottom of the expansion tank but where does it go?

Thanks Paul

Oh and ignore the jubilee clip in picture 4, he snapped the hard water pipe and lengthened it before connection to the oil thinking it was an oil feed. I'm dropping the oil/water now.
 

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Looks like a bit of a mess, I'd not be going back there at any rate.
Your P38 might be different from mine, so see what others say...but it looks to me like the block under the plenum is on the wrong way round (there are lugs to stop this happening though?)

In the first pic the left most black line is part of the PCV system, that pipe connects to the blocked off port on the drivers side rocker cover.

In the second pic that port connects to the fuel pressure regulator, underneath and back a little.

The fourth pic looks like the hard plastic pipe running from the underside of the throttle butterfly.

My terminology is a bit crap, and you never know...it might be mine that's on back to front! :D

Edit: Oh and there should have been a little black plastic oil return device in the drivers side rocker cover PCV vent, your man might have a box with lots of left over bits!
 
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Thanks for your reply, but I'm non the wiser. The regulator has no space to plug into and under the throttle housing I can't see where the water feed would go either. In answer to your 'I think under the plenum is the wrong way round' Well every picture I've seen of the p38 engine has the oil filling cap on the right and mines on the left and your right the plenum chamber looks to be the wrong way round but you can't fit it the wrong way round. I'm bemused!!!
 
The fuel pressure regulator (under the throttle cable assembly by the coil pack connector not the other device on the drivers side) should have a vaccuum line running into the plenum chamber.

I was thinkin your man might have broke the lugs getting the plenum on or off?

There are two hose connections running under the TPS and ICV into the underside of the plenum (am assuming these are to keep the butterfly valve from freezing?), the hard plastic water hose runs back to the water header and the other rubber flexi connects to the inlet manifold.

Don't think the PCV is engine critical though if your man has blocked it off I'd assume you'll get pressure building in the rocker cover. Also doubt the butterfly water circuit is critical...but think without the vaccuum you'll be getting fuel pressure problems.

I'm not an expert by any stretch and your P38 might be different from mine, but hopefully something to look at until you get a more definitive answer.
 
pcv valve is very very engine critical!!!!!!! DO NOT under any circumstances block it off! you can vent the return to inlet track to atmosphere if you wish but do not block it will blow dipstick out leak oil from anywhere and there are much worse consequences such as blowing oil seals right out engine damage etc
 
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I've found it, right at the back of the plenum on the passenger side. Now I've got an exposed piece of rubber hose with a zip tie still attached. So am I right in thinking that all I need is to connect this to the plenum valve in picture 2? Then if that's the case and picture one is correct all I need to know is where is the inlet manifold that the water pipe connects to? Thanks guys. Nearly there but now it's chucking loads of water from the exhausts, so I can safely say the repaired head isn't repaired or the other has gone too. One problem at a time, thanks again.
 

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Give it back to the garage and tell them to give it to a LR specialist or dealer to sort out at their expense....

then go to the DfT and trading standards and tell them what they have done and how they returned the vehicle to you....if the garage also does MOT's contact VOSA too....

No garage should return a vehicle in that state....
 
Like Saint says, pretty shocking stuff so you should definately be very pi**sed off with the work.

Here's a few pics to help you make sense of it anyway:

DSCF0037.jpg


DSCF0036.jpg


DSCF0035.jpg


Mines a bit rough around the edges, but hopefully some help!
 
JD said:
Like Saint says, pretty shocking stuff so you should definately be very pi**sed off with the work.
]

Mines a bit rough around the edges, but hopefully some help!
Click to expand...

Yes I'm very upset to say the least, as for yours being a bit rough round the edges, I know where there is one up for grabs for a grand....LOL

Looking at your pictures it does look like the plenum is the wrong way but how is that possible?

Also my filler cap is on the other side, has anyone seen that before?
 
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Well wonders will never cease, a few cut fingers later and the plenum chamber removed I have worked out (With your kind help) that indeed it does fit on the wrong way. I have turned it round and now (Other than the filler cap being opposite) I can correctly identify where all the pipes go. Now for the big job of removing the head. Thanks guys. Thanks a great deal. Paul
 
Glad you're making progress buddy, now when you get chance do something about the monkey that caused you this grief!
 
Both heads coming off tomorrow and thanks to everyone on this great forum it's all back together properly (Until tomorrow) I'm taking pictures as I take them off, get them on the bench and put back on so once it's done I'll make a post. I'm doing the mechanics myself and an engineer friend is overhauling the heads. Thanks again everyone. Paul
 
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