Need to Replace Head Gasket

Mazda · May 24, 2016

Need to Replace Head Gasket - Done

Well after 22 years and over 300,000 miles I finally have to replace a head gasket on my 94 Mazda B2300.

Blew a hole between 3 and 4.

I haven't done any full head replacement in over 35 years so I need a little help with the gaskets.

I'm pretty sure that you do not put any RTV on the Head Gasket but do you need to on any of the others like the intake or exhaust side. When I pulled everything apart it looked like there isn't any at all on any of them. The new one's are a Fel-Pro Set

Also I think I should just replace the water pump and thermostat while i'm at it and have it all apart. Any other suggestions you guys might have.?

Thanks

RonD · May 24, 2016

Yes, no RTV on head gasket, or exhaust manifold gasket.
I do use it on intake water passage, also on water pump gasket.

You need new head bolts, old ones shouldn't be reused, they are TTY bolts

New timing belt?

Andy D · May 24, 2016

Are you going to rebuild the engine. Is there a ridge on the tops of the cylinders, how is the lower end? On a 22yr old 300K engine there is going to be a lot of "while you're in there" stuff

OTOH,Provided the engine didn't overheat, just putting a new gasket set would prolly do OK if you needed a fast and cheap fix. I would check the head for flatness with a straight edge, so you know it is good.

pjtoledo · May 24, 2016

let me guess, its been runnin' kinda rough for the last year or so?

Mazda · May 24, 2016

Ron D

Timing Belt was done about 20,000 ago. Looks really good. I will get new head bolt too. Thanks

Andy D

Yeah no ridge. I did check the head with a straight edge, Looks good couldn't see any light under the level with a flashlight. Didn't overheat at all never has even come close. I have needed a new cat for years and the other day I had someone stop right in front of me when I was going about 80 on the freeway. Had to downshift in order to stop without hitting them and when I did I got such a loud and power full backfire that it split the weld on the cat and I suppose it was on either 3 or 4 compression stroke and blew the hole in the head gasket.

Replaced the cat finally and then it still didn't have any power so I did a compression check on her. 1 and 2 were 135 psi and 3 and 4 were only 25 to 35 psi. So had to be blown head gasket.

pjtoledo

Yes and no but I think was mostly due to the bad cat and I also had to replace the Ignition Module.

Tedybear · May 25, 2016

Naa...A little J-B Weld and no problems....

(Yeah, that's a joke)

Pick up a Haynes or chiltons for the engine information. That will have all the tear down and reassembly specs/torque specs you'll need. It's a fun project! Just take your time with it and you should be fine.

S-

Mazda · May 26, 2016

So it took me about 7 hours to do it. 3½ to pull it apart and 3½ to put it back together.

Replaced all gaskets, new head bolts, timing belt kit, new water pump. Total was 100.46 minus my 40.00 Autozone rewards. Not to bad.

Timing belt gave me a little trouble. Wish their was a pic posted as to where to place the pry bar to set the tension. Or if there is I missed it.

Runs really good now....

http://vid1268.photobucket.com/albums/jj574/bryanduncan/002_1.mp4

Thanks everyone for your help.

RonD · May 26, 2016

Good work

Have a

Thanks for posting the update

Tedybear · May 26, 2016

Glad it's up and running for ya!!

S-

tcbaklash · May 26, 2016

Mazda said:
Well after 22 years and over 300,000 miles I finally have to replace a head gasket on my 94 Mazda B2300.

This is why I wish I had this engine instead of the 4.0

MXGerry · May 27, 2016

That's high 300k quality miles, deserves new good replacement of all gaskets. Great truck

Andy D · May 27, 2016

I've done a couple OHC I-4s head R+R 30 yrs apart. First was a Datsun 1.6. a nice, simple little 4 banger and I had a very decent Clymer ? manual. Latest was a '99 CRV I should have pulled the engine.. I replaced 2 exhaust valves, checked stuff and put the head back on. 2 things:Before I took apart the twin cam Honda, I set the engine at TDC so the timing marks line up. and the rotor is on 1. If not that old just use the timing marks. and match mark stuff as you take it apart. I also backed the head bolts in 3 stages so as not to risk bending the head. My son opted to re-use the belt. So far so good 90K miles later

Will · May 27, 2016

tcbaklash said:
This is why I wish I had this engine instead of the 4.0

A head gasket isn't a "wear part". Something caused that to fail.

The 4.0 pushrod motor is the best motor Ford ever built. 160hp is enough to do any job-it's what the first Cummins-powered Dodges had. And 225ft at 2,400rpm is great low-rpm torque for a compact truck. This motor was designed and built for trucks only. It's my favorite motor.

tcbaklash · May 27, 2016

Will said:
A head gasket isn't a "wear part". Something caused that to fail.

The 4.0 pushrod motor is the best motor Ford ever built. 160hp is enough to do any job-it's what the first Cummins-powered Dodges had. And 225ft at 2,400rpm is great low-rpm torque for a compact truck. This motor was designed and built for trucks only. It's my favorite motor.

I meant more that he's got 300k on his Lima and it's still worthwhile to work on. Not a lot of engines would be at that point. I am enjoying the noticeable power over my previous 2.9L, but there's nothing I'm doing with the truck to use that power for anything practical. I would be just peachy with a 2.3L and 4.10s.

enjr44 · May 28, 2016

4.0 160 hp engine has about the same output as the 351 Cleveland two barrel did.

Need to Replace Head Gasket

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