Possible Head Gasket Failure

[boyzdad]

Ah have you managed to blow one up in 5 miles tho, Fitted it drove to work and it went on the way there

3 engines in under a week were in that car

No, not 5 miles, it took 30 for my 1st, but I had just picked it up, with a "really low mileage engine, may even be a Jap import........possibly " We also spent some time on the hard shoulder of the M42 waiting for the seized front calliper to cool down, but that's not engine related, so doesn't count!

So I reckon I win that 1 on the "p*ssed off" scoring, big wedge of cash=dead car.

What is funny from all these posts is that when I was looking to buy my latest MR2, everyone I spoke to kept telling me how "bullet proof" these engines were......

The joke of it is though, my Dolomite Sprint threw it's bearings and ruined the crank, I thought I would get another Mk1 as they "must" be so much more reliable.

Seems I am not the only unlucky one, which makes me feel a little better!

I am fitting the engine tomorrow, fingers crossed it's a goodun!

[PW@Woodsport]

Far from bulletproof,they pop like corks after 120k on average.... the 4age in general doesn't tend to reach high miles at all although there are odd exceptions.

[Ben]

Far from bulletproof,they pop like corks after 120k on average....

Mine's on 119,500

Is there anything I should look out for that signals early signs of failure? and any preventative measures I can take?

[PW@Woodsport]

thats just an average of blown engines we see,it could go on for 30 or 40k yet problem free...all you can do is keep on top of the servicing really.

[JMR_AW11]

Looking at the causes, there are loads of ways a HG could be made to fail on car engines.


1/ Engine overheat (due to failed cooling system?) seriously stresses the gasket and can lead to the well known acute symptoms of lots of smoke etc from the engine and rough running once the gasket lets go big time. (fairly common on mk1 MR2s due to complex and vulnerable cooling system?)

2/ Failure to maintain healthy coolant causes gradual HG failure due to corrosion around the gasket.

3/ overboost on SC engines

4/ pinking causes long term stress on the HG (4A-GE is prone to pinking)

5/ preignition

6/ High mileage (it's going to let go eventually)

7/ Engine and headgasket design may make it prone to premature failure


I don't know what max pressure the 4A-GE runs at on a normal engine at full chat but I'd imagine it runs very high and this must put great strain on the HG. >700PSI at a wild guess?

Chuck in some pinking caused by cheapo fuel and maybe this is a common long term contributer to 4A-GE headgasket failure.

700PSI doesn't need much of an weakness to burrow a way out...

[PW@Woodsport]

I read somewhere that the reason the HG always breaches around number 4 cylinder is due to it running hotter than the other 3 cylinders.... the explanation included it being furthest from the water pump and not as cool.... make of that what you will.

[Ben]

Is it worth replacing the HG as a preventative measure? And is it an expensive job?

[JMR_AW11]

I read somewhere that the reason the HG always breaches around number 4 cylinder is due to it running hotter than the other 3 cylinders.... the explanation included it being furthest from the water pump and not as cool.... make of that what you will.

#4 running hotter would make it more prone to pinking as well so it's double edged.

[JMR_AW11]

Is it worth replacing the HG as a preventative measure? And is it an expensive job?

Are we making you nervous?

Seriously though, just service it and thrash it. Swap the engine if it pops and then service it and thrash it...

[Ben]

Is it worth replacing the HG as a preventative measure? And is it an expensive job?

Are we making you nervous?

Seriously though, just service it and thrash it. Swap the engine if it pops and then service it and thrash it...

A little, yes! Only really cos my 2 is my daily drive, I do about 12k a yerar and its service history is a litlle patchy
I suppose there's a fair few 4a-ges around if needs be though

[System-G]

Far from bulletproof,they pop like corks after 120k on average.... the 4age in general doesn't tend to reach high miles at all although there are odd exceptions.

I must have some of the odd ones then

Old track car 130k - 15k track miles @ 7500rpm. Big ends went due to my own fault.
New track car 125k - 6k track miles @7500rpm and still pulling strong.

[PW@Woodsport]

I didn't say they all pop immediately on 120k now did i? its an average of what ive seen as an mr2 garage owner that has replaced a lot of engines.

For every engine that lasts 160k there are some that let go on 80-90k,thats why i said "on average".If yours are lasting into high miles then you are obviously servicing them well and looking after them

[System-G]

I know Paul, but all I was pointing out is I know a fair few high milers being tracked regularly with no problems. Whether they have had HG's in the past is unknown though.

Our SC's HG went within unknown mileage on the car (speedo cable hadn't been working for a while when we bought it). From the first signs of there being a problem with overheating to when we replaced the HG, took over a year including a numbe rof trackdays. We suspect the mileage was around 90k.

I also forgot about my old corolla AE92 that had over 130k on the clock and ran well wit no probs. Was sold onto a guy who intended on rallying it on the engine for a season, but lost contact and heard nothing much later.

I think the term "popping like corks" is a bit exagerated TBH.

As far as servicing goes on the track cars - new oil & oil filter every 2k - 3k miles. Fresh long life coolant every year. K&N cleaned & oiled every 6 months. New plugs every 18 months or so along with rotor arm.

[PW@Woodsport]

I think the term "popping like corks" is a bit exagerated TBH.

Perhaps if you worked in the trade and particularly on mr2's for the last ten years you would understand that comment i guess,ive literally seen hundreds all go around that mileage,but as i said there are exceptions.

[System-G]

LOL!

I spanner with a race team who run a number of cars in the Caterham Roadsports running Rover K-Series & Superlight series running Ford Duratecs most of which have less than 20k on the engines... If you wanna know about "popping like corks", come join us

This year we have the pleasure of running a few cars in the new R300 and R500 series too

I also help run trackdays and spanner at the larger events abroad with Bookatrack - you see other makes of cars with HG failures more often than MR2's

I'm not disputing you've seen plenty of 4A's with HG failures, but "popping like corks" I have to admit is a new one for me
I've seen more 3S's with lower miles go than 4A's in my 8 years of MR2 "enthusiasm"...

EDITED to add the Superlight engines (missed it out somehow... )

[PW@Woodsport]

I bow to your superior knowledge on the subject garrick,i obviously have no idea what im talking about.

Do you know how many phone calls i get per week from mk1 owners with HG issues or blown engines?

They "pop like corks" anything over 120k mate wether you accept that or not is up to you,i can only speak from personal experience running an mr2 specialist garage for the last ten years.

[System-G]

Don't take what I am saying the wrong way Paul. And I'm certainly not saying my knowledge is "superior" to your at all.
All I am saying the term "popping like corks" is a bit over the top is all

FFS, why does everyone take forums so 'kin litterally?

[PW@Woodsport]

Indeed... like say for instance someone was to take the term "popping like corks" literally.

[System-G]

[JMR_AW11]

Paul, in your experience, is the 120k mile 'pop' referring to just the HG or the general end of life for the engine?

If it's just the HG then it's not that bad really. I bet Lotus Elise owners would love that kind of HG life from a K series.

The other way to look at it is in engine rev count. These cars generally get revved high all their lives so in terms of rev life they probably fare really well.

When I first bought my MR2 in 94 I was told by a Toyota mechanic that the 4A-GE is pretty much bulletproof as along as you service it, keep the coolant system in tiptop condition and rev the engine freely but don't abuse it (eg avoid caning it up long hills etc)