Head bolts (Page 1/1)
Firezappy JUL 23, 03:55 PM
I am lost on something silly. I have a 1988 2.5 Fiero. I am changing the head gasket, not because I am 100% sure it is the issue, but I was one step away from it anyway changing the intake manifold gasket. So the head is off, and it was easy enough to get the torque values and steps. Both surfaces are shiny clean, and I am about to put it back together. In the manual I am using though it does not mention coating the threads in some sort of sealant? Was this just not done on the 88? Because I feel like most dukes needed this done. Attached below is some of the manual, I am using the 1988 Pontiac Fiero Service Manual.
Dennis LaGrua JUL 23, 04:51 PM
Not too familiar with the 88 Duke engine but a rule of thumb is to use sealant on bolts that thread into the water jacket or through any water passage but before you install the head I would first check it with a straight edge so the head gasket will properly seal. I believe that bolts 9 and 10 are the ones that require sealant before installation.

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[This message has been edited by Dennis LaGrua (edited 07-29-2021).]

theogre JUL 23, 06:04 PM
87+ is different motor 88 more so. Don't treat them same as older L4 cast engines.
BUT>>> all need New Head Bolts. Even if not "Torque To Yield" many have problem right from the Factory. So Don't reuse them.

Yes, Some engines have Some Head and other Bolts that need sealer because they "see" Coolant.
If Head and other bolts on X engine don't pierce the block and holes are dry all the time then Do Not add sealer to them.

#9 bolt gets less torque... Not sure why.
If the bolt needs sealer, sealer is lube when wet and use less torque.
Head, Block or Both maybe weaker there and use less torque so won't break.

Some Intake man bolts maybe need sealer too for same thing.
Note: Use Permatex intake gasket. This is make to prevent leaks in area. Others are same as GM gasket and #4 cyl will suck coolant very easy.
Some intake man bolts and holes get oil on them... They pierce the head at Oil Drain(s) and don't need sealer. Bit If you can't clean them, torque value is useless for them and will break something trying to reach spec w/ oily parts.

⚠️ Warning: Most FSM have many errors. Don't trust them. Many GM TSB are "updates" to the FSM for this reason but many errors are never fixed. Example: 84-86 Fiero FSM Rear Brake section is copy/past from another car and near useless. GM only fix that in 87 FSM.

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Firezappy JUL 23, 07:58 PM
A friend came over today that works on cars for a living, he helped me throw it together real quick. I am now concerned about what you mentioned about over tightening the bolts due to some left over oil though.We did put sealant on any bolts near water as well. Hopefully it's all good. Tomorrow I am going to change the oil and flush the water. But the little we ran it today it seemed great. Worse case scenario I blow up the engine and join the forums on another 3800 project xD.

It's crazy though on the lack of some critical engine information for the 88 iron duke, Haynes manual has instructions for all engines from 84 - 87 but 88 is strangely absent. Then the 'official manual' seems to assume that you just know some things.

[This message has been edited by Firezappy (edited 07-23-2021).]

theogre JUL 23, 10:05 PM

quote
Originally posted by Firezappy:
It's crazy though on the lack of some critical engine information for the 88 iron duke, Haynes manual has instructions for all engines from 84 - 87 but 88 is strangely absent. Then the 'official manual' seems to assume that you just know some things.

Haynes and other "books" are near or are useless depending on the problem. Like Most of electric data is very bad or may work for 1 year and not others. Haynes Fiero books (is at least 2 versions) don't have DIS, 700 series TBI or 88 Brakes.

FSM and TSB doc's are "written" by GM for GM Dealer Service staff. (alldata.com and Alldatadiy.com data source is from this.)
Even most Service people can't read them w/o spending a lot of time and have access to all tools listed w/in including specialty tools from GM/Kent-moore. If you think Snapon etc gets Big $... Most Kent-moore tools are higher $ then that. Even many old GM/KM tools now sold thru Ebay want $$ because most are rare to very rare.
David Riedle JUL 23, 11:12 PM
Ogre is absolutely correct. DO NOT reuse head bolt.

Anyone who works on automobiles, and tells you that this is an acceptable practice is just wrong, or really inept.

Replace the bolts, and follow the factory recommendation exactly.


Dave
David Riedle JUL 23, 11:16 PM
Ogre is absolutely correct. DO NOT reuse head bolt.

Anyone who works on automobiles, and tells you that this is an acceptable practice is just wrong, or really inept.

Replace the bolts, and follow the factory recommendation exactly.


Dave