Exhaust manifold Question
04-14-2011, 03:30 PM
#1
Exhaust manifold Question I am going to replace my exhaust manifolds on my 98 z28, it has 272,000 miles on it and the manifold bolts have never been removed. My question is should I remove them with the engine Hot or Cold? I know different materials expand at different rates and I don't want to break off any of the bolts in the Head. Also should i use some type of rust remover like Liquid Wrench? Any Help would be Great. Thanx.
04-14-2011, 03:33 PM
#2
Staging Lane
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Well if you try to remove the bolts when the engine is hot im pretty sure you'll burn your skin off! lol so remove them when its cold and they should come right out i suggest getting exhaust manifold studs while your at it.
04-14-2011, 08:01 PM
#4
I am going to replace my exhaust manifolds on my 98 z28, it has 272,000 miles on it and the manifold bolts have never been removed. My question is should I remove them with the engine Hot or Cold? I know different materials expand at different rates and I don't want to break off any of the bolts in the Head. Also should i use some type of rust remover like Liquid Wrench? Any Help would be Great. Thanx.
04-14-2011, 10:07 PM
#6
It's an interesting idea to do it with the engine hot.
What expands more when heated, aluminum or steel? This would be aluminum as steel is much more dense.
So, with an aluminum block and steel bolts, theoretically, the bolts will come out with less chance of problems when the engine is hot.
Spraying a lube or penetrating oil on the bolt will do little as it's virtually imposable to get the lube into the threads.
Exhaust manifold bolts are a crapshoot. If they're jammed or corroded into the head, there's not much you can do about it. Most of the time, these bolts come out without any problems.
What expands more when heated, aluminum or steel? This would be aluminum as steel is much more dense.
So, with an aluminum block and steel bolts, theoretically, the bolts will come out with less chance of problems when the engine is hot.
Spraying a lube or penetrating oil on the bolt will do little as it's virtually imposable to get the lube into the threads.
Exhaust manifold bolts are a crapshoot. If they're jammed or corroded into the head, there's not much you can do about it. Most of the time, these bolts come out without any problems.
04-15-2011, 12:03 AM
#7
That is what I was thinking taking them out Hot would give me a Better chance of having No Issues. Thanx for your replies.
It's an interesting idea to do it with the engine hot.
What expands more when heated, aluminum or steel? This would be aluminum as steel is much more dense.
So, with an aluminum block and steel bolts, theoretically, the bolts will come out with less chance of problems when the engine is hot.
Spraying a lube or penetrating oil on the bolt will do little as it's virtually imposable to get the lube into the threads.
Exhaust manifold bolts are a crapshoot. If they're jammed or corroded into the head, there's not much you can do about it. Most of the time, these bolts come out without any problems.
What expands more when heated, aluminum or steel? This would be aluminum as steel is much more dense.
So, with an aluminum block and steel bolts, theoretically, the bolts will come out with less chance of problems when the engine is hot.
Spraying a lube or penetrating oil on the bolt will do little as it's virtually imposable to get the lube into the threads.
Exhaust manifold bolts are a crapshoot. If they're jammed or corroded into the head, there's not much you can do about it. Most of the time, these bolts come out without any problems.
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04-15-2011, 10:47 AM
#8
I have seen where taking spark plugs out of aluminum heads while hot causes them to be blown out at a later date such as the infamous FORD modular heads. Id get the heads warm or barely over that but not hot, and yes, aluminum will expand alot more than steel. That was my reason for doing it that way and it worked perfect for me. After the bolts were broke loose they all were threaded out by hand easily.
04-16-2011, 11:47 AM
#11
No Headers, this is my daily driver and my cats are shot. Bought cats from a 2001 and they are different so this is why I am changing the manifolds, Y pipe. Yes the car still burns a little bit of rubber and runs Great! Can't beat those Chevy motors.
