# Xtrail head should be replced not machined



## barryboon (Sep 5, 2017)

Hi Guys
I would love to know what others think and /or hear of similar....the story so far..
Xtrail 2002 TI T30 auto 4 cylinder petrol.
Gets service and rego check and during this a spark plug snaps off in engine...they couldn't get it out..annoying but we wore the extra $1000 or so dollars to have the head machined and plug bored out and re seated..on top of the $800 service...bummer.
3 months later driving, in a 50km zone, and hear something go..a sort of air releasing sound..thought it had something to with the aircon system...all gauges fine.( oil/temp)....drove less than two minutes to a safe place...turned off engine...steam out the front and a split in the top of radiator ...double bummer.
Towed to a different Mechanic and is being assessed now but definitely water in one of the cylinders..not sure which.
I have been told by this Mechanic, as well as another that I called, that these heads should not be machined..as they will last only a short time then fail.
As the car was driven only a couple of minutes after I heard that noise..which was most likely the radiator giving out, I would say that the head gave out well before.
Any feed back would be awesome.
Cheers Fellas


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## rogoman (Dec 16, 2004)

The maximum that a QR25DE head can be milled is 0.1 mm (0.004") which is not very much. If it exceeds the limit, the head needs to be replaced. Also when re-installing the head, use new head bolts. Most vehicle manufacturers use Torque-To-Yield (T-T-Y) head bolts, especially on engines with aluminum heads. They provide more consistent clamping loads across the entire head-to-block mating surface. Since T-T-Y bolts are designed to stretch, reusing them can cause improper or uneven torque and clamping force resulting in a high probability of a blown head gasket. Stretched bolts can damage threads in the engine, especially on aluminum blocks, and since the bolts are weakened, they may break if re-torqued. You should always replace the bolts.


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## barryboon (Sep 5, 2017)

Thanks rogoman..I would guess that new bolts did not get used...I will ask...cheers mate


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## SeekerFor (Dec 29, 2015)

Hi Rogoman

I have a 2006 Xtrail Bonavista 2.5
Lent it out and the timing chain blew.
Tech wanted $3,000.00 Canadian to repair.

I am more than capable to rebuild the engine. And from what I have learned it is just as easy to pull the engine as it is to do the timing chain. It was burning some oil so I figured I would do a ring job and get the head done. 
Here is the issue. 
A used engine cannot be found at a reasonable price, timing kits are like $650.00 
A head is 5 to 600 

Is there any place to get parts for a rebuild at a decent price.

Another tech wanted $4,500. to repair the engine.


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## SeekerFor (Dec 29, 2015)

I have been told that you can measure the head bolts with a thread gauge and if they are not stretched you can reuse them.

Last engine I did with TIY bolts I bought new ones. 
5 Cylinder Colorado 
Still running great.


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## SeekerFor (Dec 29, 2015)

Why couldn't they get the broken plug out?

I have taken head bolts out of aluminum blocks.


I take nuts that fit into the hole after I round them off on the grinder.
I stack as many as needed.
Then I run my drill bit down the middle. The sleeve of the nuts keeps it from going wonky and damaging the block.
I use a reverse drill bit and if that doesn't do it I have a special bit that will chew through any material including tool steel. 
Now the issue is long drill bits of small diameter are almost impossible to find.
So I buy 5/16" steel brake line.
The shank of the bit fits perfect in the line.

I use a 110 volt mig and weld the bit into the line.

Works great.
I also have a snake LED lit camera that connects to my laptop so I can look right down into the work.

I have taken broken plugs out of the old V8 engines. Now that's a job and a half. Sometimes you are forced to put a Helicoil back in.


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## quadraria10 (Jul 6, 2010)

Here is a link for the timing chain kit

2006 NISSAN X-TRAIL 2.5L L4 Timing Set | RockAuto

with delivery you are looking at around 200 cdn

2006 NISSAN X-TRAIL 2.5L L4 Cylinder Head Bolt | RockAuto

these the tty bolts? If so good clearance deal.

Surprised you cannot find a head. Same engine was used in 02-06 Altima's and Sentra SER

I have a Bonavista as well. You are the first blown timing chain I have heard about. Any idea why? Did it actually break?


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