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Location:
Brisbane
Registered:
July 2003
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How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 10:00
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Are there any tell-tale signs that a 7M-GTE is about the blow its HG or does it just happen?
Any pointers before I shell over the rest of the money for the Soarer?
Cheers
Paul
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Location:
Brisbane
Registered:
June 2003
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 10:37
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When its running, does it
Blow white smoke?
Is there:
Oil in the water - look inside the radiator cap
Water in the oil - look in the oil filler cap
I doubt the owner will let you, but if he does, get yourself a bhg test kit, it tests for exhaust fumes into the cooling system.
That should help a little...
Blake.
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Location:
Brisbane
Registered:
July 2003
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 10:56
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Can you elaborate into the BHG test kit?
Where can I get one, how much, and can I do it myself?
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Location:
Brisbane
Registered:
June 2003
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 11:01
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do you know a mechanic? Or someone with a workshop should have one you can borrow. Otherwise they're available at repco from memory!
It is very similar to a pump style.
You fill up the canister on the pump with water, and this liquid ( i forget its name sorry!)
And it turns a specific colour to show exhaust gases are present in the cooling system (mine turned yellow).
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Location:
Brisbane
Registered:
June 2003
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 11:02
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so yeah you can do it yourself 
If you're not sure, do it twice.
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Location:
Melbourne
Registered:
May 2002
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 11:03
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look for bubbles in the coolent bottle after a hard drive and watery/white under the oil filler cap
Allan
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Location:
Brisbane
Registered:
July 2003
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 11:06
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The car blew its head gasket 10,000 k's ago and was fixed under a dealer warranty. I doubt they would have used a metal headgasket or known to re-torque the head.
What do you suggest I do?
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Location:
Brisbane
Registered:
June 2003
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 11:08
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take it to someone who you can trust, get them to pull down the bolts. Its worth the effort.
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Location:
Brisbane
Registered:
July 2003
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 11:10
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Should I do that after I buy it, or before?
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Location:
Brisbane
Registered:
June 2003
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 11:15
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i doubt the people will let you take it to someone, who has to pull most of the intake apart to tighten up the bolts! Just do the tests/ diagnosis we have told you about...if it clears them, then buy it and have the head re-torqued then
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Location:
Brisbane
Registered:
July 2003
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 11:18
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Lovely...
Thanks a million...
BTW, are there any MkIII/MZ/GZ20/21 forums around?
Paul
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I supported Toymods
Location:
Central Coast
Registered:
May 2002
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Location:
Brisbane
Registered:
November 2002
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Re: How to pick a Blown Head Gasket 7M
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Sun, 09 November 2003 12:19
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Once you open the bonnet, there are two things to look for.
Look on the build plate or on the front of the timing belt cover. If either of these say "7MGTE" then I'm afraid you have a blown head gasket.
Seriously, though - gunge under the oil cap (white spots/goo), a gunky looking radiator, bubbles in the coolant, gurgling/gushing sounds when starting/stopping the car, car blowing steam out the exhaust, car using coolant, car misfiring, car making less power.
Also if you pull out spark plugs if one is really clean that may be a sign.. also if you can lean waaay over and look in the spark plug holes with the aid of a torch... you will see that the pistons are black/charcoal. If one (or more) is brownish or cleaner than the others then it's probably a BHG.
If you ask someone who's been there before - retorque the head bolts NOW and start saving for a new head gasket.
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Location:
Perth
Registered:
January 2003
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Re: How to pick a Blown Head Gasket 7M
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Mon, 10 November 2003 03:51
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Headgaskets don't always blow between the cylinder and coolant jacket, I have had several fail between adjacent cylinders. The best test for a BHG is to do a leakdown test, it will tell you if the the gasket is blown and where the leak is going.
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I supported Toymods
Location:
south of the big smoke
Registered:
May 2002
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 04:01
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| 7M-Brisbane wrote on Sun, 09 November 2003 23:19 |
Seriously, though - gunge under the oil cap (white spots/goo), a gunky looking radiator, bubbles in the coolant, gurgling/gushing sounds when starting/stopping the car, car blowing steam out the exhaust, car using coolant, car misfiring, car making less power.
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i dont appear to have any off them, my car seems to be warmer than usual. actually its using a bit of coolant but it aint in the oil
what they usually charge to test it? i dont wanna folk out $110 for a head gasket if it aint needed
cheers
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Location:
sunny coast, qld
Registered:
October 2002
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 04:35
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my 1JZ has a bit of gunge in the oil cap,makes a little girgle sound when you turn it off, has a misfire (always has) and makes less power than it should. It also is very laggy, I thought this was because of it running on 5 cylinders. I don't think it is using coolant and it doesn't blow steam out the exhuast.
I was told that it was running on 5 because of either dirty injectors or a sticky lifter as the compression and spark is good.
Any one have any advice?
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 04:36
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To test for CO2 in cooling system? a few bucks, if that
All they do is put a device over the radiator cap (open) and do a chemical test to see if CO2 is coming out
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Location:
sunny coast, qld
Registered:
October 2002
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 04:46
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Doesn't the car usually overheat if you have a BHG?
mine runs at middle temp.
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 04:58
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Not ness.
If it blows from cyl to cyl, temp wont change, but power will disappear
If it blows from oil to cyl, temp wont change, but oil will be everywhere out the back
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Location:
sunny coast, qld
Registered:
October 2002
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 05:12
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so would a cylinder to cylinder blow make the symptoms that i said just before?
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 05:17
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Do a compression test
Pull out all of the spark plugs, take off the coil->dizzy lead, and do a compression test on all cylinders (warm engine, not cold)
If 1 or 2 are heaps down on others, you have BHG (or a hole in a piston/valve!)
cyl-cyl blow will look something like this
170-168-50-47-172-165, or something along those lines
GL
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Location:
sunny coast, qld
Registered:
October 2002
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 05:27
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i have had the compression tested and it was 180-190 in all cylinders.
I don't have oil leaking out the back
The car doesn't over heat.
Does that mean that i don't have a BGH?
I hope so!
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Location:
Brisbane
Registered:
May 2002
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 05:30
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Very unlikely you have a BHG then.
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 05:38
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I agree Norbie. I'd be looking somewhere else
New plugs/leads/injector cleaner.
check the check engine light, my TPS was incorrectly set causing heaps of idling issues
New Oil/filter
take off one hose at a time and clean it out thoroughly, you may find one is blocked
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Location:
sunny coast, qld
Registered:
October 2002
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 05:40
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I am glad to hear some reassurance!
After all that is why I chose the 1jz over the 7m 
Don't the 1jz's have metal head gaskets standard?
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Location:
Brisbane
Registered:
May 2002
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Re: How to pick a Blown Head Gasket 7M
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Tue, 06 January 2004 05:42
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Yes, all JZ engines have steel headgaskets and much more sensible bore spacing, which means BHG's are quite uncommon.
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