Reasons for coolant to be in spark plug well.

snwbordr02

Founding Member
Feb 9, 2002
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Bay Area, CA
About 10k miles ago my car was running poorly. Never through a code but replaced all of the spark plugs and realized #8 (driver's side, closest to firewall) was bad. When i pulled it out it was wet on the electrode and moist within the well. I thought it was gas splashing on it. Now, 10k miles later #8 went out again. It through a misfire code. I did drive it for about 30 mi running on 7 cylinders. When i pulled off the COP there was enough coolant in well to cover half of the exposed spark plug.

I have flushed my coolant within this 10k miles.

What causes this much coolant to be inside the well? Did it push up through the threads of the spark plug from inside the cylinder. No signs of leaking from the top, but i'm not certain. Needless to say, i soaked up the coolant replaced the spark plug and drove it to work and back (25 mi) and it ran fine. Pulled off the COP when i got home and it was dry. Any suggestions?
 
Coolant shouldn't be coming up from inside the cylinder. If it were in there, it should be burnt and be producing white smoke behind you.

My guess is like said above, cracked intake manifold.
 
I could be wrong on this since mine never cracked, but I don't think that is a common place for the crack to occur. I would have guessed the intake gasket since the intake just blocks the coolant passage on that part of the head.
 
jstreet0204 said:
I could be wrong on this since mine never cracked, but I don't think that is a common place for the crack to occur. I would have guessed the intake gasket since the intake just blocks the coolant passage on that part of the head.

I was also going to suggest the intake gasket. If it had a very slow leak, then it could be trickling coolant into the plug well because the water jacket is in close proximity to the #4 cylinder well.
 
jstreet0204 said:
I could be wrong on this since mine never cracked, but I don't think that is a common place for the crack to occur. I would have guessed the intake gasket since the intake just blocks the coolant passage on that part of the head.


no it's not common at all.. I have only seen or heard of it once.. I had the gasket blow out there on my own car once, but mine blew out the other way it was pouring down the back of the motor.

I would check it again after you drive it awile and see if the coolant is pooling there again.
 
hey, let me know if its the intake. I think I still have an intake from my old 01 sitting around the garage. If I do have it and you need it, it's yours if you want to pay for the shipping.


**NOTE** this is not a sale.....just trying to help a fellow stanger out.
 
Look around the engine compartment CLOSELY to see if there is a leaking heater hose or something. On trucks, this happens sometimes because there is a heater hose directly above one of the rear spark plugs. When the hose leaks it fills the spark plug well and eventually takes out a COP or a coil.
 
Thanks Dan_Soprano for the offer and to all for the input. It doesn't look like coolant is spilling anywhere else. I haven't checked any other plugs to see if coolant exists anywhere else. I will tonight. I'm going to call up the shop and try to get an appointment to have it looked at. Hopefully its just the gasket. Will update when i find out more.
 
I couldn't see the crack on my intake until I had it out of the car and in the light. The crack was on the passenger side flooding the #4 well, where one of the coolent hoses connect. No where near the "aluminum crossover" episodes. Highly doubt its the gasket, from what I read thats usually never the case.

Good Luck!
 
squares98 said:
do you have the aluminum intake crossover on your intake manifold?
There is no aluminum cross over at the rear of any 2V intake,or any cross over at all.He has an issue with #8.Even if it was cracked at the cross over at the front of the intake,you would think that the first 3 plugs would've got some aswell before getting to #8.
View attachment 427116
The only thing i can think of is that it is no longer sealed at the rear coolant passage of the cylinder head where it meets to the intake (see diagram below) or cracked at that part of the intake,and is leaking into the spark plug port. :shrug: Good luck.
View attachment 427118
 
1low03gt said:
The only thing i can think of is that it is no longer sealed at the rear coolant passage of the cylinder head where it meets to the intake (see diagram below) or cracked at that part of the intake,and is leaking into the spark plug port. :shrug: Good luck.

Thats what I said in my first post.

MBDiagMan said:
Look around the engine compartment CLOSELY to see if there is a leaking heater hose or something. On trucks, this happens sometimes because there is a heater hose directly above one of the rear spark plugs. When the hose leaks it fills the spark plug well and eventually takes out a COP or a coil.


that coolant hose is near plug #4 on the other side of the motor. That is a common problem, this problem he is having is RARE.. Too bad we will never know where the leak is, since the shop he brings it too will sell him a intake and gasket and never pinpoint wher ethe failure occured.
 
I have an appointment for tomorrow morning to bring it in. I'm debating on doing it though. I've been driving around the weekend, getting on it and it runs pretty good - felt it miss maybe once. The thing is i don't want to bring it in when its running fine because then they're going to have trouble diagnosing it. More time = more money. I never got around to checking the other spark plugs either. I'll check them tomorrow for certain and update the post.