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Forum namePerformance/Engine
Topic subject420a Head Gasket Swap FAIL.
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=126352
126352, 420a Head Gasket Swap FAIL.
Posted by Reject, Jul-02-09 10:01 AM
Hello, I am new to the 2GNT.com forums, but have been playing withs DSM's for awhile. I recently replaced the head gasket on a 97 Talon ESi. Originally I had a small coolant leak from the drivers side of the head on the firewall side.

I tore the car a part. Had the head decked and pressure tested. I took gasket remover and a light scotch-brite treatment to the block to clean off any remaining gasket material.

Put the new head gasket and head back on. Put NEW oil lubed head bolts in and torqued them to;

(in sequience of course)

Insides 20ft/lbs Outsides 20ft/lbs
Insides 50ft/lbs Outsides 25ft/lbs
Insides 50ft/lbs Outsides 25ft/lbs

and then a 1/4 turn past on all bolts.

Replaced everything and torqued everything to Haynes manual specifications.

Tried to start the car and it fired right up, but I have a small consistant drip coming from the passenger's side of the head by the firewall. It follows the timing chain cover down and drips off.

Everything else seems to be seal and seated corretly. Did I do something wrong or what? I have read on other forums that some seem to thing the torque specs that I have listed here are incorrect and it should be 50ft/lbs across all bolts at finish. I have also read that the outer bolts should be torqed to 35ft/lbs.

Any ideas would be very helpful. Thank you!

126353, RE: 420a Head Gasket Swap FAIL.
Posted by bzoss, Jul-02-09 10:26 AM
I had a problem with a small pin-hole in my top radiator hose once. It wouldn't leak noticably, only under operating temp. It was more of a myst really. Then it would condence on something, like the timing cover and drip down. I thought for sure it was coming from my water pump. I would have a shop, or do it yourself if you have the tools, do a quick pressure test on the coolant system. That is how I found my leak.
126354, RE: 420a Head Gasket Swap FAIL.
Posted by Reject, Jul-02-09 10:33 AM
Umm... No. It is leaking from the head. It is very apparent that it is leaking from the head. Any other ideas?
126355, RE: 420a Head Gasket Swap FAIL.
Posted by CODE4, Jul-02-09 10:50 AM
Per FSM specifications:

126356, RE: 420a Head Gasket Swap FAIL.
Posted by Reject, Jul-02-09 11:00 AM
K, good. That is exactly what I did give or take a couple foot pounds. I still have an oil drip out of the rear of the head.

For shits and giggles... What would happen if I decided to torque the outerbolt down another 5-10 Foot pounds? Think it would warp it?

If I remember correctly, on these heads, the bolt bottoms out anyway right? Would it make a difference?
126357, RE: 420a Head Gasket Swap FAIL.
Posted by bullettdsm, Jul-02-09 11:10 AM
Originally posted by CODE4
Per FSM specifications:

New numbers, same process (using, of course, clean holes and oiled threads on the MLS HG) .
1. 25 for the 1-6 and 20 for the 7-10
2. Then 50 for the 1-6 and 35 for the 7-10
3. Then retorque 50 for the 1-6 and 35 for the 7-10
4. Then 90* turn (1/4 turn) on all of them.

Definitive and done many times by myself with no problems.

Did you happen to reuse your old studs? Possibly you got something stuck in the edge of your headgasket sealing area? Are you positive that its not coming from your heater hose (as in slight leak onto headgasket joint) and then trailing down to that area? A leak in the area where you first saw it, is often times a small leak in the heater hose. Which may have changed position in the head switch.

126362, RE: 420a Head Gasket Swap FAIL.
Posted by Reject, Jul-02-09 12:14 PM
I doubt that it is from the heater hose. I am getting an oil / antifreeze mixture. primarily oil with just a bit of antifreeze.

I did not reuse the old head bolts. They are new.

I'll double check everything. Make absolutely sure that it is leaking from where I think it is. If I confirm that it is still leaking from where I think it is, I will try torquing it to 35ft/lbs.

In the event I retorque, do I take them to 35ft/lbs and then turn them another 1/4 of a turn or just torque to 35ft/lbs and call it good?
126365, RE: 420a Head Gasket Swap FAIL.
Posted by bullettdsm, Jul-02-09 02:24 PM
Originally posted by Reject
I doubt that it is from the heater hose. I am getting an oil / antifreeze mixture. primarily oil with just a bit of antifreeze.

Ah, I didn't catch that in your first post and your other response (mentioning oil) you posted as I posted, lol.



Originally posted by Reject In the event I retorque, do I take them to 35ft/lbs and then turn them another 1/4 of a turn or just torque to 35ft/lbs and call it good?


Ok, the official answer would be to take everything apart and redo it.

Well, now that we got that out of the way, here's what I would do. First off, you cannot just re-torque to 35. Remember you already did the 1/4 turn more? That is well past 35ft/lbs. You should just loosen them all up and re-torque (though I am a little skeptical that this is your problem).

Now, you could also just loosen up the shorties, one at a time and redo. Keep in mind that there are quite a few who have replaced their headbolts with ARP headstuds this way with no ill effects (420a and 4g63). By just doing them one at a time.

But at this point, I definitely wouldn't bother taking everything apart. I would take the shot of re-torquing

Oh yeah, do not worry about your bolts being stretched out past their limit. You can, with all confidence, re-use them at this point.

126372, RE: 420a Head Gasket Swap FAIL.
Posted by bzoss, Jul-03-09 06:51 AM
Did you use any RTV on the valve cover gasket? That thing is notorious for leaking if you just put the gasket in. All the little curves and bends really need RTV to get a good seal. That could be where the oil is coming from. Just a thought. Man, I hope you really don't have to take the head back off though.
126386, RE: 420a Head Gasket Swap FAIL.
Posted by dalesmitsu, Jul-03-09 07:58 PM
Originally posted by bzoss
Did you use any RTV on the valve cover gasket? That thing is notorious for leaking if you just put the gasket in. All the little curves and bends really need RTV to get a good seal. That could be where the oil is coming from. Just a thought. Man, I hope you really don't have to take the head back off though.


It would be a good idea also, to shave 1/8 off the head bolt either passenger side or driverside rear head bolt. I've read on here that our beloved 420a tends to have leak there.

You might wanna do a search on this subject, it could also help with the stock head bolts too.

126415, RE: 420a Head Gasket Swap FAIL.
Posted by User_22, Jul-04-09 11:29 PM
Yeah, do a good check around the block for gaps or wholes in the sealed area of the gasket.
126425, RE: 420a Head Gasket Swap FAIL.
Posted by kballard81, Jul-05-09 10:04 AM
its the drivers side firewall short bolt #7......you have to cut 4-5 threads off the bold because it bottoms out in the block......i forgot to do my last rebuild and it leaked in the spot.
126432, RE: 420a Head Gasket Swap FAIL.
Posted by bullettdsm, Jul-05-09 05:39 PM
Originally posted by Reject
I have also read that the outer bolts should be torqed to 35ft/lbs (plus an additional 90* more).

This is correct per 1998 technical bulletin of the AERA (Automotive Engines Rebuilders Association). In accomodation of the MLS head gaskets. If you are using the composite Head Gasket (not that anybody does) these numbers don't apply.

As for the passenger side head bolts leaking on certain engines; I was under the impression that the new head bolts accomodated for this. I have yet to see this problem with any of my rebuilds. Now with that being said, there is a possibility that your block bolt holes were not totally cleaned out, thus causing the rear passenger side to bottom out.

Possibility.

126525, RE: 420a Head Gasket Swap FAIL.
Posted by Reject, Jul-09-09 08:39 AM
What would the approx. ft/lbs of the 35ft/lbs plus 90deg be? About 50-60ft/lbs? I checked torque on all the bolts and the outsides were sitting at roughly 50ft/lbs and the inners were at about 67ft/lbs after doing the 35/50ft/lbs plus the 90deg turn.

This sound about right?
126526, RE: 420a Head Gasket Swap FAIL.
Posted by bzoss, Jul-09-09 09:41 AM
It would be 50ft-lbs plus a 90 degree turn...
126527, RE: 420a Head Gasket Swap FAIL.
Posted by Reject, Jul-09-09 10:50 AM
What would be? The inside? The outter bolts? What was that an answer to? My question is this;

If you torque the outer head bolts to 35ft/lbs and THEN turn the 90 degrees, what is the final torque reading(roughly)?

If you torque the inner head bolts to 50ft/lbs and THEN turn the 90 degrees, what is the final torque reading(roughly)?

Just so I can go back and double check.