97 4.0 Sahara - failed head gasket? - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ General Discussion Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 07-18-2011, 03:13 PM   #1
Jeeper
 
Join Date: Mar 2011
Posts: 20
97 4.0 Sahara - failed head gasket?

Hi Guys,

I bought a 1997 TJ 4.0 Sahara auto about 4 months ago. It's done 85k miles. I don't have any service history. It was going fine until a few weeks ago when I had an issue on the motorway (I'm in the UK).

I was driving along the motorway at about 70mph when the water temperature gauge jumped into the red and the jeep beeped. I stopped as quickly as I could on the hard shoulder, stopped the engine and got out. There was a load of steam coming out from under the bonnet, and I could hear the coolant boiling. After a few minutes when the steam had stopped, I opened the bonnet and saw that the coolant was boiling in the expansion tank and coming out of the overflow and all over the road. After a few minutes almost all of the coolant had evaporated or spilled on the road.

We called the AA out and they eventually diagnosed a failed head gasket. The guy tried filling the coolant up via the radiator cap and when the engine ran it kept ejecting the coolant back out the filler. He checked the thermostat and advised that it was really old and rusty. He took it out and said it might run better without it at that point in time due to it's age. He again tried filling the coolant, but it wouldn't accept it, it just kept spluttering out. He eventually recovered me home and advised me to go to a garage to have the fault investigated properly.

I took it to my local main Jeep dealers, as I couldn't find anywhere else over here in the UK that would touch an old jeep. They did a 30 minute diagnostic and concluded:

Carried out pressure test to vehicle.
Coolant system building up pressure, head gasket has gone.
Possible damage to head will need checking.

They quoted £943 to replace the head gasket and an extra £65 for a crack test and head skim, which they recommended.

I told them that I'd do the work myself as I didn't want to pay that much. I bought a new gasket set, new head bolts and new oil, coolant etc.

My friend and I spent 2 nights this week taking all the bits off to get at the head, and we removed the head on Thursday night. There was no obvious damage to the head at all, and when we looked at the gasket, there was no sign of a break in the rings around the gasket either. My friend has replaced a few head gaskets in his time and said that it was odd that there was no sign of the break if the gasket had gone. I took the head into a local machine shop to get it pressure tested and skimmed. They did the pressure test today and advised that there were no problems found, the head is solid and straight. They are skimming it tomorrow for me.

One thing we did notice (in attached pics) is that one of the rockers seemed to be starved of oil. Number 3 (I think) didn't appear to have any oil in it when we took the valve cover off. Does anyone know whether this is a problem and if so, what the likely cause is?

I'm collecting the head tomorrow with a view to re-fitting it with the new gasket set. I am a little concerned that the issue might be something else, given that there were apparently no issues with the gasket or the head that we could see.

One thing I had noticed in the weeks before the issue was a smell of coolant from the engine while it was hot, and there was often a small pool of what I assume is coolant (wasn't oil for sure) in a couple of the valleys on the top of the intake manifold towards the back of the engine. I cleaned this small pool up a couple of times, but it always seemed to return. I don't know if this is connected to the issue, but I suspect it could be. The oil was absolutely clean when we took the head off, no sign of any emulsification. There was also no sign of anything untoward in the coolant expansion tank, except for the lack of coolant.

Is it possible that the leak is elsewhere, like in the exhaust manifold itself? Would this give similar symptoms? Or is it possible that the gasket had gone at this side and that coolant was leaking out of the side of the head into the manifold valley?

Any advise would be greatly appreciated. I have very little experience of Jeeps or american cars, but I didn't expect to have this kind of failure on the jeep, especially the rock solid 4.0 I6 engine. The dealer was sure it wouldn't be a head gasket when I initially called them, then once they had done the test they called back to report their surprise that it was (or at least they thought it was).

Thanks in advance guys, hope I can get this sorted soon,
Robin
Attached Thumbnails
Click image for larger version

Name:	IMG_4487.jpg
Views:	119
Size:	229.1 KB
ID:	58428   Click image for larger version

Name:	IMG_4488.jpg
Views:	123
Size:	226.9 KB
ID:	58429  

Click image for larger version

Name:	IMG_4489.jpg
Views:	112
Size:	232.5 KB
ID:	58430  

__________________
1997 Wrangler TJ 4.0L Sahara Automatic, Black
1989 BMW 635 CSi Highline Motorsport Auto, Misano Red
wranglerrobin is offline   Quote Quick Reply
Old 07-18-2011, 03:43 PM   #2
Jeeper
 
neverfastenough1's Avatar
 
Join Date: Nov 2010
Location: Savannah, Ga
Posts: 925
You checked all the cylinder walls for cracks while the head was off? Does it blow out as soon as the engine is cranked, or after it is heated? If it blows out while the engine is cold, then it is exhaust in the system. If it blows out after it is heated, it could be a colapsed hose or clogged radiator, or yes, exhuast. Any milk in the oil?

neverfastenough1 is offline   Quote Quick Reply
Old 07-18-2011, 04:07 PM   #3
Jeeper
 
TJ-Q8's Avatar
 
Join Date: Aug 2010
Location: Kuwait
Posts: 583
YeAh check the cylinders sometime they can crack causing same symtoms a head. I replaced head gasket too just a week ago. I would clean the radiator on the inside too, i dont know if you guys use similiar techniques but where i lve they open up the radiotor by taking off the plastic cover. Then they pressure clean the inside, you couldnt imagne what came out of mine, hehe. Then silicone and close the plastic cover.
__________________
2001 Jeep Wranlger Tj (Maroon)
Auto for now, will be manual soon
All Stock for now too
Other vehicles:
1978 Chevy Silverado restored
2009 Harley Fat Bob
TJ-Q8 is offline   Quote Quick Reply
Old 07-18-2011, 04:20 PM   #4
Jeeper
 
Rubicon2's Avatar
 
Join Date: Nov 2010
Location: Northern Lower Michigan
Posts: 1,360
It could have been something as simple as your radiator cap. Did you have coolant elsewhere under the bonnet? Could have been coolant blowing around from driving down the road. I would have tried replacing the radiator cap first. If the cap has gone bad it would certainly cause the problem you are describing.
__________________
DO OR DO NOT... THERE IS NO TRY.
Rubicon2 is offline   Quote Quick Reply
Old 07-19-2011, 01:29 AM   #5
Jeeper
 
Join Date: Mar 2011
Posts: 20
Hi Guys,

Thanks for the responses:

- The oil was clean, no milk whatsoever.
- I don't see it blowing, there is certainly nothing when it is cold.
- When you say checked the cylinder walls for cracks, you mean within the block? I didn't really check this as the pistons obscure the view of most of the cylinder linings. I hadn't really thought about the block itself being cracked - does this ever happen?
- I think the radiator was replaced quite recently. It looks quite new and appears to be pretty clean inside. I will give it a rinse out before refilling the coolant.
- Coolant was all down the right side of the engine (facing front, so the left side sitting in the driver seat). It is also all down the inside of the wheel arch interior on that side as well. There is yellow staining everywhere on that side. You can see the yellow colouring in 2 of the pics. I would have hoped that the Jeep dealer would pick up on the radiator cap being bad, but I guess you never know. Their pressure test on the cooling system should have shown that up though, surely. They did a test, presumably with the cap off, and concluded that it was a failed head gasket.

Thanks guys,
Robin
__________________
1997 Wrangler TJ 4.0L Sahara Automatic, Black
1989 BMW 635 CSi Highline Motorsport Auto, Misano Red
wranglerrobin is offline   Quote Quick Reply
Old 07-19-2011, 02:08 AM   #6
Jeeper
 
TJ-Q8's Avatar
 
Join Date: Aug 2010
Location: Kuwait
Posts: 583
Quote:
Originally Posted by wranglerrobin
Hi Guys,

Thanks for the responses:

- The oil was clean, no milk whatsoever.
- I don't see it blowing, there is certainly nothing when it is cold.
- When you say checked the cylinder walls for cracks, you mean within the block? I didn't really check this as the pistons obscure the view of most of the cylinder linings. I hadn't really thought about the block itself being cracked - does this ever happen?
- I think the radiator was replaced quite recently. It looks quite new and appears to be pretty clean inside. I will give it a rinse out before refilling the coolant.
- Coolant was all down the right side of the engine (facing front, so the left side sitting in the driver seat). It is also all down the inside of the wheel arch interior on that side as well. There is yellow staining everywhere on that side. You can see the yellow colouring in 2 of the pics. I would have hoped that the Jeep dealer would pick up on the radiator cap being bad, but I guess you never know. Their pressure test on the cooling system should have shown that up though, surely. They did a test, presumably with the cap off, and concluded that it was a failed head gasket.

Thanks guys,
Robin
Yeah my friends block recently cracked on his 4 ltr after it heated up. I would also check the freeze plugs. Some times they tend to leAk. Good luck and keep us posted with what happens.
__________________
2001 Jeep Wranlger Tj (Maroon)
Auto for now, will be manual soon
All Stock for now too
Other vehicles:
1978 Chevy Silverado restored
2009 Harley Fat Bob
TJ-Q8 is offline   Quote Quick Reply
Old 07-19-2011, 05:57 AM   #7
Jeeper
 
Rubicon2's Avatar
 
Join Date: Nov 2010
Location: Northern Lower Michigan
Posts: 1,360
Hmmm I thought from your previous post that it built up pressure when they tested the system. They may not have tested the cap although one would think they would. I would try a new 18 lb. cap.
__________________
DO OR DO NOT... THERE IS NO TRY.
Rubicon2 is offline   Quote Quick Reply
Old 07-19-2011, 07:12 AM   #8
Jeeper
 
Join Date: Aug 2010
Posts: 466
In the few following weeks before this happened ...was the leaking coolant found under the front of your motor ? Bad water pump , was the motor blowing white smoke out of the tail pipe ? blown head gasket
hookuspookus is offline   Quote Quick Reply
Old 08-04-2011, 04:21 PM   #9
Jeeper
 
Join Date: Mar 2011
Posts: 20
Hi Guys,

Have replaced the head gasket and put everything back together. That was a fair job, took us a few evenings to get it all done. Put it all back together, put in clean coolant, brand new oil, new spark plugs, air filter, radiator cap (18lbs) and thermostat.

Went out for a drive that evening and it overheated again. It rose to just over 100 oC as I was driving, then lept into the red as I was driving up a hill and the red "check gauges" came up on the dash. We stopped and observed bubbles coming into the expansion tank through the rubber hose from the top of the radiator. The top radiator hose was very very hot - too hot to touch, and very firm to squeeze (through a towel). After it cooled down, I drove it home, and have taken it out a further 2 or 3 times, each time I get the same issue. I initially thought it might be air in the cooling system, but it's exactly as it happened previously.

Any ideas what this might be. I am now certain it isn't the head gasket. I had the head crack tested and skimmed before re-fitting, and they said it was 100%.

Could it be the water pump? I don't seem to be loosing a lot of coolant that I can detect. I do get a smell of coolant when it overheats, and I can see it boiling in the expansion tank. What checks can I do?

Thanks,
Robin
__________________
1997 Wrangler TJ 4.0L Sahara Automatic, Black
1989 BMW 635 CSi Highline Motorsport Auto, Misano Red
wranglerrobin is offline   Quote Quick Reply
Old 08-04-2011, 05:15 PM   #10
Jeeper
 
TJ-Q8's Avatar
 
Join Date: Aug 2010
Location: Kuwait
Posts: 583
Quote:
Originally Posted by wranglerrobin
Hi Guys,

Have replaced the head gasket and put everything back together. That was a fair job, took us a few evenings to get it all done. Put it all back together, put in clean coolant, brand new oil, new spark plugs, air filter, radiator cap (18lbs) and thermostat.

Went out for a drive that evening and it overheated again. It rose to just over 100 oC as I was driving, then lept into the red as I was driving up a hill and the red "check gauges" came up on the dash. We stopped and observed bubbles coming into the expansion tank through the rubber hose from the top of the radiator. The top radiator hose was very very hot - too hot to touch, and very firm to squeeze (through a towel). After it cooled down, I drove it home, and have taken it out a further 2 or 3 times, each time I get the same issue. I initially thought it might be air in the cooling system, but it's exactly as it happened previously.

Any ideas what this might be. I am now certain it isn't the head gasket. I had the head crack tested and skimmed before re-fitting, and they said it was 100%.

Could it be the water pump? I don't seem to be loosing a lot of coolant that I can detect. I do get a smell of coolant when it overheats, and I can see it boiling in the expansion tank. What checks can I do?

Thanks,
Robin
Fan clutch? Good? Is it noisy?
__________________
2001 Jeep Wranlger Tj (Maroon)
Auto for now, will be manual soon
All Stock for now too
Other vehicles:
1978 Chevy Silverado restored
2009 Harley Fat Bob
TJ-Q8 is offline   Quote Quick Reply
Old 08-04-2011, 06:25 PM   #11
Jeeper
 
necromancer_tat's Avatar
 
Join Date: Feb 2011
Location: Norfolk Virginia
Posts: 1,793
Have your whole cooling system pressure tested. If you're smelling coolant inside your vehicle there's a good chance your heater core is broken. If you're getting little pools of coolant that puddle up on your intake you've most likely got a bad intake gasket.

Either of those to problems will cause loss of pressure in your cooling system. Loss of pressure will cause the liquid inside the system to have air bubbles in it, air bubbles cause loss of cooling efficiency, which can lead to boiling of the coolant, over pressure of the system, and bursted seals and cooland leaks and steam coming out of the overflow catch bottle...

A cooling system pressure test will hopefully give you a better direction to focus your attention on.

Good luck, and if you do get it all sorted out please post your findings to give the rest of us some info in case we experience something similar.

Thanks!
necromancer_tat is offline   Quote Quick Reply
Old 08-11-2011, 07:51 PM   #12
Jeeper
 
Join Date: Jul 2011
Posts: 111
i had sort of the same problem with coolant on the rocker arms. pulled the head and it is in the machine shop. hope to put it back together this weekend

yellowlabs is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Head Gasket RidinUma WF New Member Check In 0 02-02-2011 06:39 PM
head gasket, vibration dannyobow TJ Tech Forum 5 11-12-2010 11:03 PM
Head gasket TD2020 TJ Tech Forum 3 01-26-2010 02:54 PM
replacing head gasket on 94 jeep PLEASE help jmgracing YJ Tech Forum 6 12-06-2009 07:25 PM
After head gasket replacement jbone303 TJ Tech Forum 7 11-14-2009 06:50 AM



» Featured Product

All times are GMT -5. The time now is 10:18 PM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC