Absolutely! Makes logical sense.

 

Two other culprits of course: knackered water pump and/or thermostat, also!

 

a colder bottom hose is not a problem. it will always be colder than the top one otherwise the rad is not doing its job! even after a good run my bottom hose is colder than the top one.
suggest the op takes the header cap off when the engine is stone cold. top up the header to the brim then start the engine with the cap off. Put the cap back on as soon as the car warms and the water begins to expand and come out of the header tank.
when the engine is upto temperature check the sides of the rad for leaks.
never take the header cap off when the engine is warm or hot. you will loose all the coolant over the drive!

 

Despite the rad obviously cooling the coolant, the bottom hose does still get hot - or at least have some warmth to it.

When mine had the HG failure, an airlock used to get in after going on boost - bottom hose stone cold; too high temp; coolant force out, etc, etc. Now my engine's fine, bottom hose still hot (albeit not so hot as top hose, obviously).

My coolant temps are fine - cycles between 86C and 91C (rad fans come on at 91). When on a run at motorway speeds and a little boost introduced, then temps lower to 80C, or sometimes less! Normal slow speed running temp is 83C. I do, though, have a Zero Sports 71C stat fitted.

Hope this helps the poster.

 

Thanks guys, all your advice is very much appreciated at this point. fingers crossed... and toes... and legs... and teeth, lol

my temp gauge is usually just below halfway, as long as i keep it brimmed with water, as soon as i drive it on boost for a day or two the temp will rise when i slow down or stop and my coolant level has dropped, if i dont boost at all it will be fine for a couple of weeks. it never goes all the way to the top, just over 3 quarters sometimes.

 

Yeah, airlock in there for whatever reason - carry on with your remedies/investigations that we discussed earlier...

The temp needle should stay resolutely at the centre (a needle's width below centre to be precise). When up to normal temp, if everything was okay, then it shouldn't budge!

When mine overheated and the gauge started to move, this coincided to about between 110-118C... and the needle got vertical! after about 120+

 

im sorry but to me if it sounds like head gasket as its overheating after boosting.

 

Just checked the water pump on my break and it looks brand new so must have been replaced recently so ill rule that one out.

i agree dj, that my first impressions/fears were the headgasket, which is still a strong possibilty, but im an optimist so im classing changing it as a last resort.

 

I agree - but I'm just trying to give bones hope lol.


And yeah bones, absolutely NOTHING to lose by reinstating the coolant by the correct method, etc; checking rad/stat, etc, etc. You never know...


Wish I was a "glass half full" bloke... I'm resolutely a "glass totally empty and with a big crack in the side" sap, unfortunately.

 

hey guys, good fookin news. my mate whos a mechanic, and owned a few classic scoobys, just spent the last couple of hours trying to sort my problem out. the main thing is ITS NOT THE HEADGASKET, YAY.

he took apart the whole cooling system coz i had a major airlock, flushed every pipe through with a hose and we found some of them were blocked, including the one running to the turbo. so he put it all back together and filled it up properly. we took it for a 15min blast and it was fully boosting with no fuel cut for the first time in months, the temp gauge stayed normal even after a good thrash and being left to idle for 15mins after, and there was no coolant coming out of the overflow and no bubbles either. happy days.

the only bad points from this really are iv got a small leak on drivers side of the rad, and i do get very slight hesitation at about 5k rpm when on full boost but it is literally for a split second, dont know what causes this but im gonna upgrade all the hoses now to see if it helps.

so thanks for all your help and advice guys

 

nice one! I've been following this thread and I'm hoping once I get my new radiator on and flush and refill the coolant that my problems go away too. I'm too far away from home for it to be a HG issue

 

sometimes the most simple solution to a problem is the right one. hope it is in ur case too mate.

anyone know where is best online to buy a rad? and which one to buy, or should i just get a standard one?

 

See - a bit of effort and it don't necessarily HAVE to be the HG!

Try resetting the ECU, to start from a 'clean slate' - it may just clear that slight hestation. It probably originally chucked a load of fuel in when the temps got too high, so as to try to compensate for the hotter-than-normal engine.

The hesitation should clear in time (if the reset doesn't do it immediately)...

 

"It probably originally chucked a load of fuel in when the temps got too high"
this mite also explain why it failed MOT on emissions a couple of weeks ago too. iv bought a new lambda sensor anyway which i have yet to fit so hopefully it will pass next week.

how do i reset the ecu?

 

Std OEM one is perfectly fine obviously - but pricey at around £200-300 (I think)... But alot of people have bought this one and are very happy with the price; delivery; guarantee; works fine, etc.:-

http://cgi.ebay.co.uk/SUBARU-IMPREZA...d=p3286.c0.m14

 

Scoobypedia | Trusted knowledge for everything Subaru | Knowledge / ECU Reset

 

As for the radiator - I was going to get a cheap £60 or so ebay job, but I had trouble figuring out which impreza equivalent was going to fit my legacy GT-B, so I gave in and decided to get a OE one from a forum member for twice that price. Then I remembered seing aluminium 'race' ones for around that price and thought it would be silly not to. I ended up getting a toyosports one which I got on ebay for ever so slightly less than on their site (only found their site today).

I've not fitted it yet as I'm waiting for new hoses to arrive after splitting one, but it looks very well made and fits in place (tough might not if you have a FMIC). The only problem was the holes for the bottom screws of the fans didn't quite line up - tey were off by about 6 or 7 mm. I drilled the fans with new holes in the right place and now it's all fixed up and ready to go.

It's a bit thicker than the OE radiator and is supposedly 30% more efficient.

I bought mine from ebay this one there are other makes of course but can't comment on them.

 

awesome thanks, 50quid will do me fine, have enough left for silicone hoses now too.

 

I got one of those for my older legacy and the little pipe at the top snapped off whilst fitting it After I fixed it it was ok but didn't have the car for long. The plastic end tanks are a known weak point which is why I decided to get the aluminium one.

 

I ordered a sillycone hose set from the same company I got the rad from. Not samco, but should still be better than the old ones! £65 I think for the set but that included sipping to france

 

thanks for the info, was thinking of an alloy one but for 50quid u cant really go wrong, if it breaks it goes back.

 

how many hoses were in the set? ill av a look at their site. ebay got them really cheap too, i want all the rad and coolant hoses aswel as the turbo hoses and air intake hose. cant find anywhere that does them all in one kit?

 

oh and joz ur a ledgend, cheers for ur help on this thread mate. unfortunately for u now though i am gonna hound u everytime my car needs something, lol

 

I got the hoses from the ebay link I posted above, check that seller's items you should find the set - I got the one for the GC8s which should be the one you need (not exactly right for me but most seemed right). There are loads of other sets too, so best to check ones with pictures and see what matches the hoses in your engine bay if you're not sure which one is right.

 

True, but same with the ali one, only it should last a lot longer

 

Not cheap, but...

Roger Clark Motorsport - RCM Product Detail

Roger Clark Motorsport - RCM Product Detail

 

Hmm, they do look nice. i have seen a 8 peice Coolant set on merlin motorsport website (samco) for £137. bit pricey considering its the same amount for the trubo hoses aswell. what do u make of the SFS hoses? cant see there being much difference apart from the price

 

I've got top and bottom silicone rad hoses of unknown(!) make - £25, and they've been perfect since fitment about a year ago!

Don't HAVE to pay out for Samco... I'm sure SFS ones are fine.

 

good to hear mate, i shall be ebaying away this weekend

 

good to hear, ill be ebaying away this weekend then.