Heater not blowing hot air after overheat

[Zach]

Yea not good. I was thrashing my wrx around the highways when I stopped at the post office to do some stuff my temp gauge was nearly max. It cooled down and I drove it home without letting it overheat by stopping for long breaks to let it cool off.

Coolant was overflowing out of te bottle next to the battery and the heater does not blow hot air. I did go off a nasty gutter while reversing shortly before the overheat happend could it have shaken something? I think its headgasket :-[ really hope its not but I think it is.

[funkytown]

bypass your heater core at the back of the block. probably a blocked heater core causing flow issues and then overheat.

To test:

- warm car up with heater blowing warm

- put your hand on the inlet pipe to heater core, should be warm hot.

- put hand on outlet to heater core pipe - if hot, not blocked, if cold - blocked heater core as above.

V unlikely to be HG in the first instance, although overheating it wont help it doing HG\'s subsequently

[Zach]

 funkytown said:

bypass your heater core at the back of the block. probably a blocked heater core causing flow issues and then overheat.

To test:

- warm car up with heater blowing warm

- put your hand on the inlet pipe to heater core, should be warm hot.

- put hand on outlet to heater core pipe - if hot, not blocked, if cold - blocked heater core as above.

V unlikely to be HG in the first instance, although overheating it wont help it doing HG\'s subsequently

Wow man thanks for that ;D! Ok now I just need to findout how to "Bypass my heatercore"

[funkytown]

dont bypass it just yet. as you might not have to.

test it as i listed above - and report back. have to do it with the car warmed up, but obviously not overheating.

[Zach]

[/img] I have the to hoses apart now I need to put them together. Im thinking about running a pipe right thru the middle of them but the middle pipe will have to be smaller. How small will too small be

[Timmah]

 Zach said:

[/img] I have the to hoses apart now I need to put them together. Im thinking about running a pipe right thru the middle of them but the middle pipe will have to be smaller. How small will too small be

Read here: http://www.clubsub.org.nz/forum/index.php/topic,11161.0.html

I think following Funky\'s advice before pulling hoses apart would of been the best thing to do.

[Zach]

All Done. Clean bypass.

It over heats still but I noticed the temp gauge wont move until about 2 mins of driving then it all of a sudden goes from cold to mid way. then another minute or so of driving it goes from mid way and starts heading towards H again. Im really hoping it\'s not a head gasket but its starting to look that way lol

Thanks for the tip though I learnt alot there which was pretty cool in its self

[funkytown]

you realise you now wont have any heater.. ever.

also have you rebleed the system properly? and did it suddenly heat up with boost?

[madmike]

Sounds like you have toasted the head gasket mate....

Easy way to tell is...

Take it for a really really quiet drive with no boost at all..

I mean NO BOOSTING..

It should not overheat.

Then stop and boost it for a couple of mins through gears. If the temp shoots up then you deff have a toasted headgasket

[Zach]

 funkytown said:

you realise you now wont have any heater.. ever.

also have you rebleed the system properly? and did it suddenly heat up with boost?

I dont need the heater at all I\'ll default the piping to the heater again once I clean/replace the heatercore. I filled any missing coolant up b4 the conversion I have not put any in afterwards. And yea its started heating up after Boost how did you know lol

[Zach]

 madmike said:

Sounds like you have toasted the head gasket mate....

Easy way to tell is...

Take it for a really really quiet drive with no boost at all..

I mean NO BOOSTING..

It should not overheat.

Then stop and boost it for a couple of mins through gears. If the temp shoots up then you deff have a toasted headgasket

Guess that means problem Diagnosed. I have booked it into the local garage and told them its most likely a HG. Whats the price range usually for this? I\'m thinking around $2000

[funkytown]

if headgasket leaks - when you boost it the hot hot air for the cylinders supercook your coolant.

no boost means not enough pressure to get past the HG and super heat the water.

[Zach]

Thanks funkytown I appreciate yours and everyone else who posted help, really I do

When I take it to get new Headgaskets will they be replacing other things aswell because the overheat would msot likely damage the rings and clutch plate aswell

[Zeus]

 Zach said:

replace the heatercore.

Not a cheap item, and is also a pain to get to

[Zach]

Yea pulling the dash apart is no quick fixer but Ill do it over a weekend

[lachlan]

Ffs boost has nothing to do with blown head gaskets . Go and look at peak cylinder pressures for a NA motor and peak cylinder pressure for a Turbo motor .

It has over heated . Water has boiled . The heater core is the highest point so it loses water first .

First thing to do is re fill it properly and bleed the system . Its complicated. Get someone who is competent to help you .

It may have just lost some water slowly over time causing it to boil over . When did you last check it ?

You potentially haven\'t fucked head gaskets but will do very soon if you don\'t sort it out

[funkytown]

dude - what mikes described above happens, seen it first hand on race car. i had a link log of it somewhere.. was fine totally off boost, gave it some beans and would instantly overheat. HG\'s were toast

[madmike]

I can tell you funky and I both have first hand experience of blown HG...

Mine was fine until you boosted. Then it blew coolant out.

I know of a least three other motors that have done the exact same thing.

The last one was only three weeks ago.

So before you FFS me you better have got your shit all in a nice little row...

[funkytown]

also seen it on an evo at the dyno, drove fine but man did it shovel water out under boost / WOT

[Zach]

Do they only change the headgasket? Or will they change a few things. Does it cost around 2g for them to pull the engine and replace just the HG? or does it cost more/less?

[funkytown]

not sure on the cost chap, but they should inspect and replace bits as required.

given kms\' you might look at freshening up the bearings? new seals and bits check the head and cases are still flat.

might be easier / cheaper to hunt for a new long block?

get a proper HG failure test done though dude. just to make sure.

[Zach]

Yea thats exactly what I was thinking. After they check it and conclude it si the HG i\'m thinking about just getting a rebuild or longblock

[madmike]

 lachlan said:

Ffs boost has nothing to do with blown head gaskets . Go and look at peak cylinder pressures for a NA motor and peak cylinder pressure for a Turbo motor .

It has over heated . Water has boiled . The heater core is the highest point so it loses water first .

First thing to do is re fill it properly and bleed the system . Its complicated. Get someone who is competent to help you .

It may have just lost some water slowly over time causing it to boil over . When did you last check it ?

You potentially haven\'t fucked head gaskets but will do very soon if you don\'t sort it out

Go back and have another think about your cylinder pressures mate...

Your getting vacuum when inlet valve closes and psi when inlet valve closes confused me thinks...

[ADIKT]

 Zach said:

Yea thats exactly what I was thinking. After they check it and conclude it si the HG i\'m thinking about just getting a rebuild or longblock

good excuse to forge her up and chuck some other tasties at it? Of course it would all depend on how thick the OPs wallet is

[Zach]

lol