Author Topic: Post head gasket replacment issures. (Read 4048 times)

victor.askew · « **on:** November 11, 2011, 08:27:10 PM »

Hello to all. I am new to this site ( yesterday) but not new to BMW ownership ( almost 20 yrs). I look forward to meeting new car lovers and hopefully making a few new friends along the way. A few questions but 1st a bit of background:
91 BMW 318I , removed the cyclinder head due to loss of coolant and liquid/ steam at exh/ tailpipe. Machine shop inspection finds a unweldable crack running across # 2 cylinder. Found a good replacment head at Double 02 located in Hayward Calif. Machine shop preforms a valve job, all new intake and exh valves and guides are installed, cam's and towers frm the old head are installed onto the new head.
The rebuilt head has been installed, The Vac lines clutter under the intake manifold has been removed as per the posts I ve read on this site dealing with that matter. The hot wire located inside the MAF box roof was cleaned with carb cleaner. New water pump installed.The fuel injectors were covered in carbon, this was removed with carb cleaner and a soft plastic brush. The injector manifold was filled with carb cleaner and left to soak overnite. New oxygen sensor installed. 2 new coil packs for cylinders ( 1 & 2) were installed, all new spark plug wires and plugs installed. The car will start but the idle is very rough, I have rechecked the few remaining hoses for vac leaks. Used hose clamps on all hose conn's. The ICV ohms out @8.6.
Question 1: Is it possible for the ICV to ohm out in spec and still malfunction, causing the engine to stumble, not want to idle at all when cold and barely idle when hot? Can carb cleaner be used to clean out the insides of the ICV?
2. The intake manifold gasket and the fuel inj manifold gasket, should a gasket sealant be used when reinstalling these back in place. I did not as when I took the engine apart none had been used. Can this be a source of 1 big vac leak?
3. The valve cover bolt holes had to all be heli coiled before it could be installed . There is not any visible oil leaking anywhere from this gasket but is it a possible point for a vac leak even though it isnt leaking. Thanks in advance

DesktopDave · « **Reply #1 on:** November 11, 2011, 10:10:08 PM »

Welcome to the club...sorry to hear you have troubles though. Sounds like you're off to a good start though.

Question 1...I'd say that the ICV might be working properly but sending the wrong amount of air into the motor. Vac line cracks are the usual culprit, but the ICV is in a feedback loop with the CPS and O2 sensor. The two temp sensors can also make for a rough idle. Did you do the stomp test to see if codes have been set?

I used new OEM paper gaskets when I put my manifold back together last time. Others recommend gasket sealers. I'd think they'd help, but the gasket alone should be enough.

Those valve cover bolts strip out a lot. The cam gasket is thick, I'm guessing a vac leak is unlikely there as well, unless one of the spark plug seals is missing.

Nelson_40 · « **Reply #2 on:** November 12, 2011, 09:52:30 AM »

Quote from: victor.askew;108010

2 new coil packs for cylinders ( 1 & 2) were installed, all new spark plug wires and plugs installed.

I vaguely recall reading somewhere that there are two sets of coils available and if mismatched sets are installed the car will of course not operate correctly.

Quote from: victor.askew;108010

The intake manifold gasket and the fuel inj manifold gasket, should a gasket sealant be used when reinstalling these back in place. I did not as when I took the engine apart none had been used. Can this be a source of 1 big vac leak?

I have had no issues using just plain gaskets in those applications, but there may be some damage on the intake port area of the new head. So going back through the intake manifold and applying sealant to the lower manifold gasket on the head side may be a good idea. There are also two locating dowels in the lower manifold which can be mismatched,damaged or missing entirely and can cause a very hard to detect vac leak.

Another possible issue could be caused by poor mating of the throttle body to the upper intake manifold now that the heater plates are presumably absent.

victor.askew · « **Reply #3 on:** November 13, 2011, 02:13:31 AM »

Update: I had a huge vacuum leak, the injector manifold was not making full contact with the head along the lower edge. Out of my line of sight. I had to use a insp mirror to see the gap. I used spay on copper gasket sealant on this gasket and the lack of this being touched upon removal confirmed this and there was a clear contrast between the manifold and it. Its all together and purring like a fat kitten now. I had already installed heli coils imto every single one of the valve cover bolt holes last week as about 8 of them were bad. Thanks guys for your feedback.

DesktopDave · « **Reply #4 on:** November 13, 2011, 09:52:01 AM »

Aha...I posted in your other thread to see if you fixed the problem...I see you have. Excellent work there.

Those little cam cover bolts always get stripped out. It's so easy to overtorque them. I only tighten them maybe 1/4 turn more than hand-tight.

victor.askew · « **Reply #5 on:** November 14, 2011, 08:14:15 PM »

I picked up my new coolant hose conn fitting tday, the one that is located along side the left side of the engine block. One of the nipples was brittle and broke off while I was hooking things back up . There was just enough nipple left intact to get the bypass hose onto it for testing sat nite. Btr safe than sorry so out it goes. I had moments of fun doing this, learned alot but Im in no rush to repeat the entire job due to a $20.00 plastic part failing on me!!! Then Im back on the road.

victor.askew · « **Reply #6 on:** November 17, 2011, 07:17:39 PM »

The job has been completed at last. I put close to 200 miles on the car yesterday and today. Idel is smooth, engine revs very smooth, the coolant temp is rock stable holding steady just before the mid point on the temp guage. power is good. I do have a follow up question, A ticking noise can be heard when the revs are increased. the location of this ticking appears to be from within the intake manifold, Is it possible for the fuel injectors to cycle loud enough to produce a auduble ticking that goes away when the rpm drops back into 850/900 rpm range? My other thought is the lifters, can they become loud and produce a ticking noise? Im using mobil 1 15/50 oil.? Thanks in advance.

Isamemon · « **Reply #7 on:** November 20, 2011, 01:52:42 PM »

my first thought is an injector
you might want to keep in mind that the next time you have to take it all apart, or if indeed it is an injector now, upgrade to the ford four pintle injectors
( well still made by bosch, but a ford mustand application)
better mpg, better idle

you can buy em on line "rebuilt" or on fleabay or pull em yourself at a wrecking yard

victor.askew · « **Reply #8 on:** November 21, 2011, 07:59:12 PM »

Quote from: Isamemon;108199

my first thought is an injector
you might want to keep in mind that the next time you have to take it all apart, or if indeed it is an injector now, upgrade to the ford four pintle injectors
( well still made by bosch, but a ford mustand application)
better mpg, better idle

you can buy em on line "rebuilt" or on fleabay or pull em yourself at a wrecking yard

Ahhh. Thanks for this feedback.

bbarnumboy · « **Reply #9 on:** November 29, 2011, 12:13:14 PM »

So mine blew once before because the plastic coolant pipe failed on the block.

2 years later i thought it went again but i had the crack

1 year after that the gasket blew again. This one really pissed me off because i went cometic MLS and arp head studs. and i still blew it. So i went for the stock gasket with ARP head studs and has been fine.

victor.askew · « **Reply #10 on:** November 29, 2011, 08:09:08 PM »

That looks like the same type of crack that I had in my #2 cylinder and 2 burned exh valvers in that cylinder also.