Cyliner head removal 2004 4.6

[xlrlist01]

Hello all

Does anyone know if it is possible to remove the left bank (2, 4, 6, 8) cylinder head with engine in car?

The official way is to drop the front and rear subframes and work on the exposed engine, there is no mention of in-situ, even though there is a special tool to hold the timing chain, without taking the timing chest off. Maybe it can be done in-situ, but dropping the subframes is quicker and easier anyway?

TIA

(I'm currently trying to diagnose a slight loss of coolant and having eliminated everything else, I'm left with the cylinder head, but that passes all tests too. At ~50,000 miles, this is an unusual problem too, if it is that. I also get a P0308 (mis-fire on #8) code from time to time at start (only), hence putting the two together.)

 

[RubyRod]

Did you perform a coolant pressure test? You can get a pressure test kit at most of the local auto parts stores as a "free loaner" tool. This should help you find where the coolant is leaking.

If you have a head gasket that's just starting to leak it might not show up with the engine cold. Neither coolant pressure test or compression test will find it. It may only occur when the engine is warm. Not a test I want to perform. You might try what they call a cylinder leak down test. If there's a weak point in the head gasket you should see some evidence of air in the coolant. You may have to let the system sit for a while before the air passes through the weak spot in the gasket when the engine is cold though. If the gasket is failing it will show up. Eventually.

Good Luck

 

[mickeytee]

A presdure test is the best way to check. Pull the number 8 plug and look at it. It shoukd show signs if water is getting into the system. Also check the oil .you might pull the valve cover and check the headbolt torque. You did not say what year your car is. The coolant line that runs under and to the trottle body is a known cause of leaks at the molded in tee. Wont leak until it gets warm. Also the water pump. Unless you have run it hot you most likely do not have a head gasket issue

 

[xlrlist01]

Did you perform a coolant pressure test? You can get a pressure test kit at most of the local auto parts stores as a "free loaner" tool. This should help you find where the coolant is leaking.

If you have a head gasket that's just starting to leak it might not show up with the engine cold. Neither coolant pressure test or compression test will find it. It may only occur when the engine is warm. Not a test I want to perform. You might try what they call a cylinder leak down test. If there's a weak point in the head gasket you should see some evidence of air in the coolant. You may have to let the system sit for a while before the air passes through the weak spot in the gasket when the engine is cold though. If the gasket is failing it will show up. Eventually.

Good Luck

This is very useful information, thanks.

The pressure test has been repeated with engine hot and once again it passes easily. However, compared to cold engine, the pressure did drop about the width of the pointer (ie hardly anything at all) in about 80 seconds, compared to over three minutes when cold (to see any movement in the needle at all).

The leakdown test is an option yet to try, but could be arranged.

 

[xlrlist01]

A presdure test is the best way to check. Pull the number 8 plug and look at it. It shoukd show signs if water is getting into the system. Also check the oil .you might pull the valve cover and check the headbolt torque. You did not say what year your car is. The coolant line that runs under and to the trottle body is a known cause of leaks at the molded in tee. Wont leak until it gets warm. Also the water pump. Unless you have run it hot you most likely do not have a head gasket issue

Agreed.

There are no signs of problems with any of the spark plugs. Oil and sump good. Oil filler cap also good. No smell of coolant in exhaust.

Car is early 2004. Year is in title of this posting.

Water pump was replaced. Can't find any evidence of leaking from any external source.

Agree, checking headbolt torque is a good idea.

A compression test did come up with unexpected data, although a pass. #1-7 all around 155-160 psi. #8, 180psi. #8 was repeated after all the others and again was 180psi. Odd.

 

[xlrlist01]

Did you perform a coolant pressure test? You can get a pressure test kit at most of the local auto parts stores as a "free loaner" tool. This should help you find where the coolant is leaking.

If you have a head gasket that's just starting to leak it might not show up with the engine cold. Neither coolant pressure test or compression test will find it. It may only occur when the engine is warm. Not a test I want to perform. You might try what they call a cylinder leak down test. If there's a weak point in the head gasket you should see some evidence of air in the coolant. You may have to let the system sit for a while before the air passes through the weak spot in the gasket when the engine is cold though. If the gasket is failing it will show up. Eventually.

Good Luck

Thanks for the advice both Ruby and Micky.

The question remains though.

I have an excellent relationship with my Cadillac dealer who know this car well (and like it a lot!). We are all scratching our heads over what is wrong, with the view that although the head gasket is passing all the tests (including looking for CO2 in the coolant and others I have listed above), this just has to be an early and unexpected head gasket failure.

The question my dealer has agreed with me to ask here is: "Can the head gasket be replaced with the engine in situ?"

My dealership have looked up all XLR head gasket jobs carried out by other dealers (there are not very many) and all of them have dropped the engine/transmission out on their subframes, as per the manual, lifting the chassis and body up off the engine/transmission. It is a big, if relatively straight forward job (a lot of unbolting and bolting).

My question is: is engine out essential, or simply easier than working in situ? Does anyone know?

TIA

 

[justdennis]

I had a leaking heater core in my 2007 V and it completely saturated the passenger side insulation under the carpet. It was like that when I bought it so I don't know how long it was leaking before the previous owner knew about it. I would think you could smell it and it is a long shot but it's worth a check.

 

[mickeytee]

Agreed.

There are no signs of problems with any of the spark plugs. Oil and sump good. Oil filler cap also good. No smell of coolant in exhaust.

Car is early 2004. Year is in title of this posting.

Water pump was replaced. Can't find any evidence of leaking from any external source.

Agree, checking headbolt torque is a good idea.

A compression test did come up with unexpected data, although a pass. #1-7 all around 155-160 psi. #8, 180psi. #8 was repeated after all the others and again was 180psi. Odd.

I had a leaking heater core in my 2007 V and it completely saturated the passenger side insulation under the carpet. It was like that when I bought it so I don't know how long it was leaking before the previous owner knew about it. I would think you could smell it and it is a long shot but it's worth a check.

Fromwhat im resding you sound like you are dying to remove the headgaket. If your leak is so small you cannot find it with a leakdown where one cylinder is a little higher than the others which is totalky normal on a used motor. You are looking to spend 5-7000$ on a leak repzir. Im sure the head cn be pulked wjthout the engine removed. Ive not done one but at most you might have to drop the front subframe a td. It gas engine bolts removed the head just sitson the block . if you are going with tge dealer body off then you might as well seal the pan, replace the other headgadket, do the timing chsin guides or just drive the car and add a little coolant. If its a headgadket it will get worse in time. With good low mileage engine for 1000$ id never even consider rebuilding one orvtearing into one. Especially an 04 . i also agree if you cnnot find it externally then id check the floor and the heatert. Ive never seen a leak yet that cannot fe fkund with a oressure. Heck. Coolant die in the system With a black light finds a drop a day leaks. Plus a simple cap test on the overflow will show if exhaust gases is getting into the system . ive never seen one of those fail to spot a headgasket leak. Im not sure you stated how large a leak after what period of driving.. 04 had bad radiators. They crack on the upper pasenger side at the overflow tube. The hose can seal the crack except at higher temps and pressure. Also tge radiator tanks leak onthe lower side crimp. You can see them crude up a slight amount but usually on the front side hidden by the ac condensor. With so many engine parts no longer available tearing into it woukd only be an option with me when it dies. Theres no stopping point. Intake can crack when removing. When you have it off o you save labor and put a starter on that may fail? Defiantly the knock sensors and if the cam covers off the vvt actustors and magnetic controllers for sure. Maybe even totally upgrade with heads studs. Id look at the value of the car and be aware that when the trunk leaks and 90% of them do you are looking at another 3-4000$ in module replacement. If you could do it yourself and know 100% its a headgasket, id try. However read about all the engine diwn to repair a smll oil leak that comes back and for some reason they seem to many times need a steering rack when they put it all back together if you have no history of the radiator being replaced that woukd be something that must be done at some point in tbe very near future so id start with that. Id be very concerned with spending tons of money with a shop that cannot find the problem for 100% sure with all the technology we have now. The misfire coukd be a bad injector or coil or plug.all would allow excess carbon to build up. Carbon is soft.makes for a great seal on metal to metal parts. valve to head. Equals higher compresdion. But when hot can ignite cauing a misfire.

 

[xlrlist01]

Fromwhat im resding you sound like you are dying to remove the headgaket. If your leak is so small you cannot find it with a leakdown where one cylinder is a little higher than the others which is totalky normal on a used motor. You are looking to spend 5-7000$ on a leak repzir. Im sure the head cn be pulked wjthout the engine removed. Ive not done one but at most you might have to drop the front subframe a td. It gas engine bolts removed the head just sitson the block . if you are going with tge dealer body off then you might as well seal the pan, replace the other headgadket, do the timing chsin guides or just drive the car and add a little coolant. If its a headgadket it will get worse in time. With good low mileage engine for 1000$ id never even consider rebuilding one orvtearing into one. Especially an 04 . i also agree if you cnnot find it externally then id check the floor and the heatert. Ive never seen a leak yet that cannot fe fkund with a oressure. Heck. Coolant die in the system With a black light finds a drop a day leaks. Plus a simple cap test on the overflow will show if exhaust gases is getting into the system . ive never seen one of those fail to spot a headgasket leak. Im not sure you stated how large a leak after what period of driving.. 04 had bad radiators. They crack on the upper pasenger side at the overflow tube. The hose can seal the crack except at higher temps and pressure. Also tge radiator tanks leak onthe lower side crimp. You can see them crude up a slight amount but usually on the front side hidden by the ac condensor. With so many engine parts no longer available tearing into it woukd only be an option with me when it dies. Theres no stopping point. Intake can crack when removing. When you have it off o you save labor and put a starter on that may fail? Defiantly the knock sensors and if the cam covers off the vvt actustors and magnetic controllers for sure. Maybe even totally upgrade with heads studs. Id look at the value of the car and be aware that when the trunk leaks and 90% of them do you are looking at another 3-4000$ in module replacement. If you could do it yourself and know 100% its a headgasket, id try. However read about all the engine diwn to repair a smll oil leak that comes back and for some reason they seem to many times need a steering rack when they put it all back together if you have no history of the radiator being replaced that woukd be something that must be done at some point in tbe very near future so id start with that. Id be very concerned with spending tons of money with a shop that cannot find the problem for 100% sure with all the technology we have now. The misfire coukd be a bad injector or coil or plug.all would allow excess carbon to build up. Carbon is soft.makes for a great seal on metal to metal parts. valve to head. Equals higher compresdion. But when hot can ignite cauing a misfire.

Thanks Micky

Your suggestion re re-torquing the head bolts: Is that a generic suggestion or have you known that work on a N* motor?

All excellent advice. I can rule out: plugs, coil packs and injectors. And fuel pump!.

The misfire is for a max of 10 seconds on cold start. Long enough to set the P0308 code. After that, perfect.

The coolant loss is very slight, though definitely there.

I have taken to removing the coolant pressure cap when I park up. This appears to have stopped the (very slight) mis-fire on cold start, reinforcing that the problem is a HG failure.

The coolant cap is fine.

I am considering changing to a waterless coolant, which has a virtually zero vapor pressure.

There is no smell of coolant at all. It is very pungent. Ok, I drive with the roof down, but all the same, there would be some kind of smell. There isn't.

I have checked the "T" piece most carefully, it is perfect.

Re other points: Agree re other HG, yes to timing chains and tensioners, knock sensor too. Radiator was upgraded to a V, same time water pump (and thermostat) was replaced. I am some way from agreeing to this HG job! More I have been discussing with dealership what might be wrong and what is worst case.

I monitor the trunk for leaks.

VMTs

 

[xlrlist01]

I had a leaking heater core in my 2007 V and it completely saturated the passenger side insulation under the carpet. It was like that when I bought it so I don't know how long it was leaking before the previous owner knew about it. I would think you could smell it and it is a long shot but it's worth a check.

Thanks. Good suggestion, can't find a leak (or any smell at all).

 

[mickeytee]

If you pull plug 8 and pressure the system you sill be sble to hear water lezk. A look at the plug will tell you if moisture in the system plus. A cheap carbon monoxide test will tell you if there is any leakage in the system. Those never fail. Ive only known of one person who had loose bolts. They rsn it hot but thought tgey vould mske it home. Once the engine is hot, it must be shut down immediately. Its an aluminum engine and does not take excessive hezt. Knowing he most likely cooked the motor he pulled tge overs and retorqued the heads . one or two were a little loose. He drove it fir years after that. As far as the v rsiator upgrade. I think people are getting ripped off somewhere. The v and the base all share the dame radiaror. The part number did change in 06 that replaced the 04/05 part number but that was the only radiztor available. A bdtter option is a double ow aluminu for a vdtte . very minor mofificstion to gdt double the cooling fir half the money of the oem. And i believe the oem is discontinued. Id crank it up xhut it doen and pull the plug. Many google sites will tell you how to read it. I teplace every car that comes in the shop with metal tees on the return hose. Ive seen them only show a leak when its capoed and air put on them.ive got a psrts car ill be temoving the intake and a head off of in the next couple days. Ill ket you know what i find. There is ome misinformation as to which cyl is number 8 out thete. Which one are you calling 8

 

[xlrlist01]

Micky

Once again, you are a mine of useful information.

Agree, a useful test would be to get an airline and hold pressure for an extended period on #8. Monitor coolant levels.

The carbon monoxide test came up with an easy pass.

Ok, run hot. Yes, this might be the history. Unknown to me the main cooling fan seized years ago. I got caught in heavy traffic and yes the temperature went up high, but not too high. Eg the N* didn't go into limp mode (it has that limp where it runs on the left bank for a while, pump just air through the right bank to cool it down, then swaps over). However, it was hot and the only time that happened. By chance I was going to the Cadillac dealer for a warranty job (that oil leak on the front timing chest, fix was a thicker gasket). So I had them check the HGs very carefully at the time. All ok, but I do wonder.

The radiator upgrade was after the OEM 2004 was unavailable and only 'V's could be sourced. The V radiator has extra fittings which are capped off.

Thanks for any information from the parts car re taking the head off with engine in car.

Re re torquing the head bolts. These don't have a torque rating IIRC. Instead they are snugged down (to a torque) and then it is angles after that. I am thinking of applying a 5 degree turn to each headbolt, with a torque limiter on the wrench.

#8 is left hand bank, at rear, ie nearest driver.

Best wishes

 

[xlrlist01]

Quote: "I've got a parts car ill be removing the intake and a head off of in the next couple days"

Micky, can I ask a favor if I may?

Before you take the heads off, please could you get a torque wrench and keep increasing the torque setting until the head bolts just start to tighten, then tell me the torque you had to use.

I know this isn't a perfect science, but it would give me a clue as to what sort of torque I will be expecting/looking for if I try tightening the head bolts on my X.

TIA

 

[mickeytee]

I can try that. . as far as the radiator to clear it up most xlr have two sets of coolers the 04/05 did not. The v uses an external cooler . aftermarket cheap radiators at the parts store are for 04-05 06-09 need both sets of coolers and have the quick connect snap in fittings. All xlrs show one part number now 04-09 base or v. If you run the 99$ ebay you need to run an extetnal oil cooler.
If you got it circulating anf the cm test was negative just keep wa watch on jt and the leak will get to the point you should find it. I highly recommend if anyone has the car start to get hot and it goes into limp mode ,. Stop. Park it, get it towed. These engines go 200,000 miles with good oil changes and are the one thing you can count on being dependable but dont let them run hot.

 

[xlrlist01]

I can try that. . as far as the radiator to clear it up most xlr have two sets of coolers the 04/05 did not. The v uses an external cooler . aftermarket cheap radiators at the parts store are for 04-05 06-09 need both sets of coolers and have the quick connect snap in fittings. All xlrs show one part number now 04-09 base or v. If you run the 99$ ebay you need to run an extetnal oil cooler.
If you got it circulating anf the cm test was negative just keep wa watch on jt and the leak will get to the point you should find it. I highly recommend if anyone has the car start to get hot and it goes into limp mode ,. Stop. Park it, get it towed. These engines go 200,000 miles with good oil changes and are the one thing you can count on being dependable but dont let them run hot.

Thanks Micky.
I'll look out for any information you can provide. I have a work colleague with a high-end Snap-On torque wrench which can do both torque and angle, he says I can borrow it! With your data I'll have something to set it too.

 

[mickeytee]

It took 65 pounds to loosen them and it appears the started to move tighter at 85. But as a tiraue to yield bolt that stretches ill have to do a littke research andcask someone that knows more than me if you can actuall depend on that. I soukd think pjtting 85 on them to check woukd not be a problem. While you are there tightnen the 10-12 intake bolts they do loosen up. The torque is 1/4 inch ratchet snug. Haha. I forget the inch pounds but ill look . they will all either be tight or loose with a 1/4 inch drive seems like 75% i check are loose but if they have been tighten once they stay tight

 

[xlrlist01]

It took 65 pounds to loosen them and it appears the started to move tighter at 85. But as a tiraue to yield bolt that stretches ill have to do a littke research andcask someone that knows more than me if you can actuall depend on that. I soukd think pjtting 85 on them to check woukd not be a problem. While you are there tightnen the 10-12 intake bolts they do loosen up. The torque is 1/4 inch ratchet snug. Haha. I forget the inch pounds but ill look . they will all either be tight or loose with a 1/4 inch drive seems like 75% i check are loose but if they have been tighten once they stay tight

Once again, thanks very much Micky.

The question I have outstanding, is roughly what is the torque to deliver the fourth stage of HB tightening.

It starts at a torque of 30 Nm (22 lb/ft) (stage 1), then stage 2 is +60 degrees, stage 3 is + 60 degrees and stage 4 is +60 degrees. Ie a total 180 degrees (or half a turn), in three stages, after the initial snugging down. The bolt threads have to be clear and smooth running too. It would be interesting what a new bolt reaches at the end of stage 4.

I might also have spotted why the sub-frame front and rear is dropped (ie engine/transmission out) for cylinder head removal. The snag is the timing chain. There is that special tool with the hooks to hold the tension on the timing chain when removing the sprockets (EN 46327). However, that tool sits on the edge of the head. So, if it is possible at all, a cord would need to be tied to the chain and tension transferred to the cord while the special tool is removed. The head could (perhaps) be lifted up, then somebody needs to put tension on the chain and the cord dropped through the head cavity. It might be possible, but not with one person. Will take two or possible three to manage keeping tension on the chain at all times.
The option is to drop the front suspension, take the steering rack off, revealing the nut on the harmonic balancer, which can then be removed and the timing chest cover removed. If this was needed, then agree, replace chains and tensioners at the same time!

 

[mickeytee]

And you will need two crankshaft bolts . one your torque and stretch and the other you then replace the first one with ive sent email to a friend to see what ort of final torque these wind up with.

 

[xlrlist01]

And you will need two crankshaft bolts . one your torque and stretch and the other you then replace the first one with ive sent email to a friend to see what ort of final torque these wind up with.

Thanks Micky. Yeah, makes sense. I'll await the reply. (I guess you mean head bolts not crankshaft bolts!)

 

[mickeytee]

If you pull the front cover to do the chains and guides you have to pull the crankshaft pulley. Then you will need two cranshaft bolts to reinstall