Rats.. literally (overheating legacy)

[Durty-Sanchez]

The TT started overheating last week, had a look under the bonnet and found 2 dead rats - the buggers had chewed holes in the coolant hoses that connect to the ICV. Anyway, it had gone unnoticed (and un-smelt) for some time and some corrosion had set in. Replaced the ICV and hoses but noticed that the coolant water (1 year old) was brown with rust.

Topped it up with coolant anyway as I'd give it a flush the following week. Drove sweet for 2-3 days (~300kms) then all of a sudden started overheating again. Opened the bonnet and seen it had blown all the overflow tank coolant out and there wasn't much left in the header tank either. Topped it up with water and drove home at 50k to stop it overheating (sat around 1/2 way, went higher if I went faster).

Went to re-do the coolant today, took ages for the coolant to drain from the bottom radiator hose. Shoved the hose in it and cranked it up, came out fine then, but was still brownish after 5 minutes. Sealed it up then started to refill it with coolant but it struggled to let it through. Took an hour to get 2.5 litres in to it (the coolant bottle). Started up the engine after that with hose ready incase a huge airbubble went, but nothing.. infact, after a while it started pushing coolant back out the header tank (lid was off).

Top radiator hose is hot when up to temperature, so are the turbo return lines.. bottom radiator hose was cold, not even luke warm. Have it booked in for a compression test on Wednesday incase it's head gaskets, but in the meantime anyone got any other ideas? I'm thinking if its not HG's that there's a monty block somewhere - and has been for a while, and all that corrosion is coming out in the water. Heater sucks btw, so that's possibly a culprit.

Thanks!

[Guest]

I had these problems before, one was a thermostat playing up and other was a air lock in the cooling system due to a hairline crack in the top tank, so just bleed the system by topping it up with water thru the top radiator hose, after that went good or another week till i found and fixed the leak

[zarnah]

hg

[Durty-Sanchez]

Yea I have a horrible feeling it may be HG, but that doesn't explain the other problems though. There's some big block in there somewhere to stop it draining and filling.. might blast the hose through just the heater core and see if I have any luck. It's getting a compression test on weds so that'll be either the good or bad news

[Munkvy]

Have you pulled the thermostat out? As if thats dead that would fit most of the symptoms.

[subieboy]

 Munkvy said:

Have you pulled the thermostat out? As if thats dead that would fit most of the symptoms.

The old Rule: New coolant means new thermostat.

[Durty-Sanchez]

Nah not yet, got a new one from CPA today but didn't have time, will be flushing it again in a day or two to get rid of all the rusty water so will swap it then. Keen to find what it is that corroded so badly though!

[Guest boostin]

If there's that much crap in the system, the heater core is most likely blocked. Its the heater flow that opens the thermostat.

No (or low) heater flow = no thermostat open = engine overheats.

If the thermostat checks out ok, try bypassing the heater by looping one of the heater hoses back. See if that solves the problem.

[Durty-Sanchez]

The verdict.. blocked radiator. Headgaskets came back as fine (to everyones suprise).

[Guest]

hehehe yep be surprised how many people scrap their engines due to a supposedly blown headgasket when infact it was other factors involved unrelated to the engine itself overheating and engine is still good condition... just like the $20 i payed for the engine i gave to my mate which still going hard a year later in his legacy lol

[Durty-Sanchez]

Or... not the verdict, as it turns out. Radiator was blocked, heater core was blocked.. all cleared out now but car still overheats. ??? With the header cap off there are visible bubbles appearing if you rev it, but when checked with head check fluid they aren't exhaust gas. So where are they coming from!

There's no visible leaks, heads are sound.. could it be the turbo seals (if the water jacket even has seals..)? At least if they went the water would be escaping in to the intake/exhaust. Doesn't overheat as badly as before, but needle still moves quite quickly up and down (used to be stable as a rock, even when giving it stick). I'm getting a rash from all the head scratching on this one..

[smokn4]

Bro had the same prob its a air lock in radiator you gotta loosen the bit where you drain the radiator then squeeze the radiator hose until a constant flow comes out then should be sorted.

[log1call]

A few points...

Doing a compression test hardly ever show up a headgasket, not unless it's really, really blown anyway in which case the compression test is a waste of time.. The engine only has a couple hundred pounds at best when cranking. It has hundreds when it's running.

Doing a leak down test is also not reliable for the same reasons.

The teekay hrdrocarbon test is the surest single test for leaking headgaskets.

In this case, there could be a build up of sludge in the lower part of the cylinders causing localised boiling. A blockage anywhere can cause the same symptom. The overall temperature can be fine but there can be boiling in one localised place.

The commonest problem with subarus though is the well known air lock. Fill them with water, raise the front of the vehicle, idle till fully warm(fans cycling several times) topping up as necessary, put the cap on and go for a short drive. let it cool and check the water in the radiator again. If the water has gone down top it up and go for another short drive then recheck it after cooling down. Keep repeating this procedure till you have a full radiator when you check it cold.

Rats... they will eat wires in cars as well. If you have rats in your car parking area.... poison the little bastards!

[Durty-Sanchez]

Compression test was fine, head-check fluid stayed blue so that's fine. Airlock in the block sounds like a possibility.. the heater and radiator were well blocked, so I would not be suprised if the block was in the same condition.

As for the rats.. there's mouse traps everywhere, but they're not big enough to catch these sods!

[log1call]

Yeah well seriously, they will eat wiring, and bonnet insulation, hoses, anything!

Unfortunatly the only really good way to be sure the blocks are clean is by taking the heads off... unless you have any faith in those radiator flush chemicals they sell.

[Guest boostin]

Teekay tests and Subaru's don't mix. By the time the test shows a blown head gasket you will have a 3m jet of water out of the filler neck. The best way is your nose. Sniff the bubbles at the filler. If they smell like exhaust, you have a blown gasket.

And the slightest blockage in the heater core will cause overheating. It doesn't matter how many times you flush it or how much pisses out when you stick the garden hose down it, its just not flowing enough. Try bypassing the heater core.

[log1call]

Ha, by the time you smell a headgasket.... you will have a burnt nose!

Agree about the heater... to a degree. If it's totally blocked the thermostat will be very late opening, but if it flows enough to open the thermostat, and everything else is working correctly, then it won't by itself cause overheating.

[Durty-Sanchez]

So as it turns out there may not have been an airlock/blockage afterall.. the (1 year old) water pump had shreded itself down to one fin. Cambelt + new pump could be worse I suppose

[Durty-Sanchez]

Clearing out the camera and thought i'd share the damage..

Although the impeller fins look corroded I suspect the corrosion set in after they were torn off by whatever went through it.. you can see only 2 fins remain, and they're completely bent under by whatever that was.