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Old 01-30-2013, 11:49 AM   #1
ScoobyDrift
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Default Turbo and SOHC Gaskets

Can a 2.5L Turbo Head Gasket work on a SOHC?
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Old 01-30-2013, 01:51 PM   #2
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I believe it's the 05-07 STI headgasket that will work. It's something like that. Someone else more knowledgeable can correct me.
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Old 01-30-2013, 03:15 PM   #3
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I've seen people use sti gaskets as a replacement since they are thicker
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Old 01-30-2013, 06:13 PM   #4
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Quote:
Originally Posted by alt14 View Post
I've seen people use sti gaskets as a replacement since they are thicker
Except, they are thinner. 0.024"(or .027) versus a stock SOHC gasket thickness of 0.040".


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Old 01-30-2013, 06:26 PM   #5
alt14
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Hm.. I've always heard they were thicker and that's why people used them. I guess I misread, in that case it wouldn't it cause a failure sooner?

Last edited by alt14; 01-30-2013 at 06:33 PM.
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Old 01-30-2013, 07:23 PM   #6
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No, you would use them because they are MLS (multi-layer steel) compared to the stock garbage graphite coated gasket. The difference is pretty small. Part number is 11044AA642
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Old 01-30-2013, 08:35 PM   #7
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Ahh that's what it is haha thanks
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Old 02-01-2013, 02:52 AM   #8
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Does this carry over to newer n/a cars? Shoud I get a headgasket set for a 2010 STi for my 2010 2.5i?
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Old 02-01-2013, 04:46 AM   #9
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no. around 09 they started putting MLS gaskets in them. Also the cooling passages in the heads changed so the holes in the older 2.5 turbo gasket don't line up quite right. I think they use -770 which is the same as the 08+ sti.

And are the headgaskets on your 2010 leaking?
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Old 02-01-2013, 06:59 AM   #10
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All 2.5 gaskets you buy new from the dealer are MLS. Even for the 96-98 DOHC engines.

Up to 2006 all coolant passages for SOHC and DOHC 2.5L heads are the same, there are several gasket thicknesses available. After that the coolant pattern changed, therewith also the head gaskets.
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Old 02-01-2013, 07:58 AM   #11
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Ok so would OEM be a good choice or should I go with something else? They are not leaking yet but I am at 71k and planning to do the timing belt kit in the next couple months and I have been seeing alot of these failing around 100K so since I'm going to be getting into the car anyways figure might as well make a weekend of it. Planning on a light weight crank pully and all new belts and hoses while I'm at it.

Last edited by Bababou; 02-01-2013 at 08:21 AM.
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Old 02-01-2013, 08:09 AM   #12
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I think what he was asking was your 2010 is leaking.. meaning after a certain year, yours included they started using the mls gaskets and the chance of them failing is lessened.
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Old 02-01-2013, 08:36 AM   #13
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I see so save the headache and extra cash and just watch it to see what happens and deal with it when it shows signs of a problem.
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Old 02-01-2013, 11:21 AM   #14
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It's better to replace it as a precaution than to wait and see until it happens. Then you need to deck the block (that's where the problem has it's root cause).
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Old 02-01-2013, 12:19 PM   #15
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I will be getting my timing belt and valve cover gaskets (spark plugs seals are leaking) done later this year and may also get the clutch changed as well as the TOB is very noisiy. I am considering getting the head gaskets done at the same time to save on labor charges as well as to avoid having to have them replaced in the near future. At this time (97k mile) they are not leaking.
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Old 02-01-2013, 05:23 PM   #16
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Quote:
Originally Posted by Marnix View Post
All 2.5 gaskets you buy new from the dealer are MLS. Even for the 96-98 DOHC engines.

Up to 2006 all coolant passages for SOHC and DOHC 2.5L heads are the same, there are several gasket thicknesses available. After that the coolant pattern changed, therewith also the head gaskets.
Last I checked that is not true, here in the US at least. The non turbo SOHC gaskets from about 99-09 are graphite coated ones. If you have one of those cars and go to the dealer for gaskets that's what you'll get, hence my recommendation to use the -642 turbo gasket. The DOHC phase 1 gaskets you get at the dealer are MLS (but thicker than the SOHC and turbo).

Quote:
Originally Posted by JohnM10 View Post
I will be getting my timing belt and valve cover gaskets (spark plugs seals are leaking) done later this year and may also get the clutch changed as well as the TOB is very noisiy. I am considering getting the head gaskets done at the same time to save on labor charges as well as to avoid having to have them replaced in the near future. At this time (97k mile) they are not leaking.
They are probably not going to since you have metal gaskets. Of course I can't gurantee that but it isn't something I would worry about changing. I have the worst car for headgaskets and am not worried since I put in the updated MLS parts.
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Old 02-02-2013, 02:20 PM   #17
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because I just asked my mechanic since I'm booked for wednesday to have this done, apparently all the gaskets according to him, are graphite, (for 2.5rs/i) the only mls ones are the STI gaskets, and these are factory parts from the dealer.

I told him I'd eat the extra cost of having heads machined so I can switch to the sti gasket. We'll see how that goes.
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Old 02-03-2013, 12:51 AM   #18
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Call Cometic and get a set of their gaskets. You won't be sorry.


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Old 02-04-2013, 01:30 PM   #19
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Quote:
Originally Posted by jamal View Post
Last I checked that is not true, here in the US at least. The non turbo SOHC gaskets from about 99-09 are graphite coated ones. If you have one of those cars and go to the dealer for gaskets that's what you'll get, hence my recommendation to use the -642 turbo gasket. The DOHC phase 1 gaskets you get at the dealer are MLS (but thicker than the SOHC and turbo).
Your dealer must be selling outdated stock. I haven't seen anything but MLS gaskets at my dealership for a few years now. Pretty sure even the SOHC Ej25 gasket was changed to MLS on one of the several updates over the years.
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Old 02-04-2013, 02:30 PM   #20
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I don't think so. Someone I know just got a gasket kit for their 02RS and it came with the old gaskets, and the online parts dealers still list 11044AA633, which looks like this:

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Old 02-05-2013, 01:03 PM   #21
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I'll side with Jamal on this one. As far as i know:

The EJ251 and the EJ253 use by default the 11044AA633. Single layered steel.

EJ251 owners sometimes replaced their HG with the 11044AA642, MLS, used in the 04-05 EJ255 and 04-06 EJ257.

Now, for some reason I read that EJ253s can use the 11044AA670, itself used in the 06-08 EJ255. Can't confirm that though.

To add to the confusion, there is also the 11044AA770, used in the EJ257 2008+ - although it appears to look the same as the 670.
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Old 02-05-2013, 01:09 PM   #22
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670 and 770 are the same thickness and construction, but the 670 is specifically for the 07 sti and then the 770 is on the 08+ and new n/a 2.5s. The difference is the cutouts for the cooling passages in the head. I think I have pictures of everything around somewhere.

Last edited by jamal; 02-05-2013 at 02:05 PM.
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Old 02-06-2013, 12:20 AM   #23
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it'd be nice to clear that up once and for all. So 642s for EJ251 and 770 for EJ253? Is there any difference in between coolant passages on the head in these two N/A engines?
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Old 02-06-2013, 01:00 PM   #24
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Maybe I'm mistaken. Wouldn't be the first time. I just know I won't use anything but an MLS on my own engines.
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Old 02-06-2013, 07:19 PM   #25
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Like Matt above, I only use MLS gaskets and rarely from the OEM parts bin. I admit I'm lost on all the latest part numbers for gaskets.

I also admit that I don't see return work for failed MLS gaskets.....


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