XJ XJ8 / XJR ( X308 ) 1997 - 2003

Things don't look good. Coolant leak, overheated, misfires and knock

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Old Aug 22, 2016 | 07:53 AM
  #21  
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Did you check the valve clearances?
Especially on the zero compression one?

I should not worry on the seals, mine looked perfect too, but I had oil in 7 out of the 8 holes.
New seals solved it, just checked after 1.000km.
 
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Old Aug 22, 2016 | 08:05 AM
  #22  
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Yeah I'm going to check the valve clearances next, I just need to pick up a feeler gauge and a large enough socket to turn the crank.
The only thing still worrying me is the knocking I heard when I last started it to back it into the garage. All this would be for naught if the bottom end is no good, which at this point I am still considering an unknown.
 
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Old Aug 22, 2016 | 09:24 AM
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When you turn the engine over turn clockwise from the front only. If the knock was more of a tap it might be a dropped valve seat. This is easy to spot because the offending valve will not return all the way. You won't need a feeler gauge to spot it.
 
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Old Aug 23, 2016 | 03:27 AM
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Ugh... I had this very issue years ago.. Ended up being coolant hoses blown and pump...
Originally Posted by OUScooby
Driving to work this morning when suddenly and warning light goes on and "low coolant" appears on the dash, and the temp gauge spikes suddenly. I pull over as quickly and as safely as I can. I manage to get a coworker to bring me some coolant, refill it but when I start it back up its just puking it out, and now the engine is misfiring as it idles.
I call AAA and use the last of the four tows I get for the year to tow it home and call off work for the day. I have to drive it for a min just to back it into the garage, and now its knocking as well as missing.
I'm starting to pull things apart right now, coolant leak seems to be coming from under the throttle body on the passenger side, there is a line coming out the firewall that I think is the culprit. But as I pull off the intake to get in there to examine closer there is a lot of blow by coming in through the head breather. Not enough that the intake track is coated with oil, but a significant enough amount to worry me, especially giving the knock.
Code reader produced the following codes p0300 multiple random misfires, and p0301 through p0304 misfires on cylinder 1, 2, 3, 4, as well as p0705 trans range sensor, but i think that last one is unrelated. I've also got pending codes for p0305, p0306 & p0308, misfires on cylinders 5, 6, & 8 and p1316 and p1111
I'm going to see how thing are once I fix this leak, but I'm not hopeful. I think the motor is done.
 
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Old Aug 26, 2016 | 09:44 PM
  #25  
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Originally Posted by princemarko
Ugh... I had this very issue years ago.. Ended up being coolant hoses blown and pump...
I couldn't find any leaks in the hoses, but I'm going to change them anyway, might as well since I've got the supercharger off, same with the thermostat, I've already got that coolant pipe off and I imagine a new thermostat is relatively cheap so why not? Not sure I'll do the water pump, I'd like to be able to test it but I'm not sure how I'd do that with the car already in pieces.
 
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Old Aug 26, 2016 | 09:48 PM
  #26  
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So no new updates to report, its just hard to find time to do anything on the car during the week, but I've been thinking about it all week and I'm starting to formulate a plan.
I'm going to attempt a valve job myself. I've never done one before so I don't know if its within my scope of abilities, but I'm fairly mechanically competent and willing to learn how to do it. Then with the valves reseated (or replaced if any of them bent) I'll do another compression check. If it comes back with no compression then I move on to the head gasket and continue from there.
Sound like a reasonable plan? Or am I getting over my head?
 
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Old Aug 26, 2016 | 09:52 PM
  #27  
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Originally Posted by OUScooby
I couldn't find any leaks in the hoses, but I'm going to change them anyway, might as well since I've got the supercharger off, same with the thermostat, I've already got that coolant pipe off and I imagine a new thermostat is relatively cheap so why not? Not sure I'll do the water pump, I'd like to be able to test it but I'm not sure how I'd do that with the car already in pieces.
I am not sure what your year of built is, but if you want to be sure, visually inspect the vanes (you will need to take the pump off for that), and check the bearing.

Although original 1998, my pump's vanes were perfect, but the plastic sealant ring kind of disintegrated upon taking off, and the bearing was not that smooth.

For peace of mind, I purchased a new one from Rockauto, less than 50 US.
Came with a new seal.
 
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Old Aug 26, 2016 | 10:41 PM
  #28  
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I don't know how far along you are but I find it easier when you put the engine back together to put what you can in gallon food storage bags. For instance I'll coils off and put them in a bag with their bolts and mark the bag as to what side they came from. I do this for everything so when I put it back together I don't have to figure out what bolts go where and since they are together you don't loose any.

When you take the heads off don't turn them upside down until you remove the cam buckets. If you do some will fall out and you might not know which valve they go to. Get a storage box or something similar to what I have in the photo. I mark it l for intake 1-8 and E for exhaust 1-8. Make sure you put everything back into the same spot. Also be careful not to scratch or damage the cam caps or the cams.

If you are not sure about something don't be afraid to ask. It's better to ask than to make a costly mistake.

Good luck

Did you check the valve clearances yet?
 
Attached Thumbnails Things don't look good. Coolant leak, overheated, misfires and knock-20160823_163941.jpg  

Last edited by BobRoy; Aug 26, 2016 at 10:57 PM.
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Old Aug 27, 2016 | 06:17 PM
  #29  
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Originally Posted by BobRoy
I don't know how far along you are but I find it easier when you put the engine back together to put what you can in gallon food storage bags. For instance I'll coils off and put them in a bag with their bolts and mark the bag as to what side they came from. I do this for everything so when I put it back together I don't have to figure out what bolts go where and since they are together you don't loose any.

When you take the heads off don't turn them upside down until you remove the cam buckets. If you do some will fall out and you might not know which valve they go to. Get a storage box or something similar to what I have in the photo. I mark it l for intake 1-8 and E for exhaust 1-8. Make sure you put everything back into the same spot. Also be careful not to scratch or damage the cam caps or the cams.

If you are not sure about something don't be afraid to ask. It's better to ask than to make a costly mistake.

Good luck

Did you check the valve clearances yet?
Thanks for the advice. I do the same thing with the bolts in plastic bags whenever I'm doing a job involving removing multiple parts, then I write on the bag in sharpie what it is. I have zip ties with little tabs for labels which I put on hoses and and fittings and number them. Going back together just match number to number.
I haven't checked the valve clearances yet I had no time in the week to get to the car, and today I've been spending leasing the cheapest car I could find. It's funny, I've got four cars and I'm still without a reliable way to get to work.
 
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Old Aug 27, 2016 | 06:23 PM
  #30  
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So one question, like I said I've never done a valve job before, but I was under the impression that it was done without removing the heads. Is that correct?
 
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Old Aug 27, 2016 | 07:40 PM
  #31  
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Correct. The valves come out in the combustion chamber of the head.
 
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Old Aug 27, 2016 | 09:22 PM
  #32  
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Originally Posted by OUScooby
So one question, like I said I've never done a valve job before, but I was under the impression that it was done without removing the heads. Is that correct?
Incorrect, you have to remove the heads to do a "valve job"
 
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Old Aug 27, 2016 | 10:53 PM
  #33  
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Don't mean to scare you but your engine will look like the photo below.
To do a valve job you will have to remove the heads. The timing cover will needed to be removed and the cams will need to come off because the head bolts are under the cams.

After you get the head off you will take the cam buckets off. Then you'll need to use a valve spring compress to compress the springs so you can remove the two retainers. When the retainers are off and the compressor is removed the springs will come out and the valve can be removed. The second photo shows the valve springs still in the head.

I think if you have zero compression on a cylinder you most likely dropped a valve seat. I have a head at my shop with the dropped valve seats and I can post a photo of it tomorrow.

If you check the clearances it will help us dianose the problem. If you have any other questions contact me tomorrow.
 
Attached Thumbnails Things don't look good. Coolant leak, overheated, misfires and knock-20160704_114859.jpg   Things don't look good. Coolant leak, overheated, misfires and knock-20160710_162257.jpg  
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Old Aug 28, 2016 | 06:30 AM
  #34  
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Thanks for correcting me, guys, I miss read his question.
 
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Old Sep 3, 2016 | 08:47 PM
  #35  
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Ok so I've finally got some time to make some progress on this, my girlfriend is out of town and its a three day weekend so no distraction.
I've check the valve clearances I've got three stuck, likely bent, valves, the rearward most valve on the pass on both the intake and the exhaust on the passenger side, and the rearward most intake valve on the driver's side. They all had valve clearances of around 0.079 or higher. All the other intake valve had a clearance between 0.008-0.010, and all other exhaust valves had a clearance of 0.010-0.012 expect for one exhuast valve on each side which had a lower clearance of 0.008-0.010.

Here are the results of the valve clearance check, (I still don't know the cylinder order so I'm just listing them driver's side/pass side front to back):

Driver's side:
I1: 0.008-0.010 E1: 0.010-0.012
I2: 0.008-0.010 E2: 0.010-0.012
I3: 0.008-0.010 E3: 0.010-0.012
I4: 0.008-0.010 E4: 0.010-0.012
I5: 0.008-0.010 E5: 0.010-0.012
I6: 0.008-0.010 E6: 0.010-0.012
I7: 0.008-0.010 E7: 0.010-0.012
I8: 0.079-0.080 E8: 0.008-0.010

Pass Side:
I1: 0.008-0.010 E1: 0.010-0.012
I2: 0.008-0.010 E2: 0.010-0.012
I3: 0.008-0.010 E3: 0.010-0.012
I4: 0.008-0.010 E4: 0.008-0.010
I5: 0.008-0.010 E5: 0.010-0.012
I6: 0.008-0.010 E6: 0.010-0.012
I7: 0.008-0.010 E7: 0.010-0.012
I8: 0.089-0.090 E8: 0.083-0.084

With both an intake and exhaust valve on the pass side stuck open it expalins the zero compression, and the stuck intake valve on the drivers side explains the low compression.With clearances that large, I think its safe to assume that I've got three bent valves, and that the valve will need to be replaced and that a valve adjustment will not be enough.

Onward to pulling the heads!
 
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Old Sep 3, 2016 | 10:30 PM
  #36  
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So I've removed the intake manifolds and fuel rails, and reached a good stopping point for the night to pack things up and get some dinner. Tomorrow I'm going to tackle removing the exhaust manifold (simple enough task but getting access to the nuts looks like it might prove tricky) and removing the timing chain cover.
But that's about as far as I feel confident going with out some sort of how to or factory service manual. I'm worried especially about screwing something up when removing the timing belt.

I did find one nice surprise today. When I took off the intake manifold, this was revealed to me. It seems a vacuum hose and its protective shielding decided to melt itself again the hot engine. And its not just the plastic cover that melted, the rubber vaccume hose also completely melted inside it. Never seen anything like it.








Not sure where this vacuum libe should lead to, but its just another on the list of parts to replace for when I put this back together.
So far I've got a few brittle vacuum lines that snapped as well as some "T" connectors on vacuum lines. The vacuum line connector on the throttle body broke off in my, as hand, as did the temperature sensor on the coolant outlet pipe and coolant hoses. This on top of new gaskets for the intake & exhaust manifolds and the super charger, as well as head gaskets and valve gaskets, head studs, and I figure I might as well replace the timing chain tensioners, they don't look worn but they as the older plastic ones so might as well replace them while I've got everything apart. Add to this a new thermostat and maybe do the water pump too.
Any thing else I should look into changing while I'm taking the motor half apart?
 
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Old Sep 3, 2016 | 11:41 PM
  #37  
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It looks to me like you proably have 3 dropped valve seats. You will have to take the heads to a machine shop to have them replace the seats and whill they have the heads have them do a valve job and set your clearances.

To remove the heads I didn't remove the exhaust manifolds. I removed them with the heads. Just take the four nuts off at the exhaust manifold and catylitic converter. Soak them with PB blaster because they usally have a little rust.
 
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Old Sep 3, 2016 | 11:54 PM
  #38  
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For a x308 manual.

Go to the stickies at the top of x308 page
Click on how to
Click on downloads tech files
Click on tech files
Click on X308 workshop manual

It's a large file about 2,000 - 3,000 pages.
 
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Old Sep 4, 2016 | 02:56 AM
  #39  
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Originally Posted by BobRoy
It looks to me like you proably have 3 dropped valve seats. You will have to take the heads to a machine shop to have them replace the seats and whill they have the heads have them do a valve job and set your clearances.

To remove the heads I didn't remove the exhaust manifolds. I removed them with the heads. Just take the four nuts off at the exhaust manifold and catylitic converter. Soak them with PB blaster because they usally have a little rust.
A HUGE +1 on all of this!!
Don't remove the exhaust manifolds until the heads are on a bench. Take both heads to the machine shop and let them do their job. If the one head is salvageable, they'll hot tank the heads, mill the heads, grind the valves and seats and adjust the valve clearance. It'll cost about $600 - $800 for the pair to have done. I spent an enormous amout of time doing my own valve job only to find out that I had to send one of them out because a few valves wouldn't hold liquid after I lapped them. I'm also making a heavy assumption that you don't have access to any bucket shims like I did. Another reason why you should send them out.
 
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Old Sep 4, 2016 | 08:58 AM
  #40  
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Another thought.
When you get the heads off DON'T TURN THEM UPSIDE DOWN TO LOOK AT THE VALVES. Put the cams back in. You only need to finger tighten them. If you turn it over without the cams in half of your cam buckets will fall out and you won't know which valve they came from. I know because I did it once and only once. It looks like your other valves have the correct clearances. If those valves only need to be lapped in they might not need to be adjusted and could save you a few dollars.
 
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