Rally_matt

Hi people, newbie member here after a little advice from those with more experience!

On Monday last week I picked up a 51 plate, WRX with an oil leak (oil drain plug - solved!) & suspected head gasket problem. Since then I have been having a look over it, (around the other projects!) and I can't seem to find a lot. On driving it back home there was no steam/smoke from the exhaust, no bubbling in the header tank, on the one try I got, still pulled like a bee-atch, sounding like a gorilla raping a wasp & felt solid with no knocks or bangs.

It has definitely been serviced recently, it's obvious from the new parts all over it, from the log book it's been well looked after and only had one keeper from new. After dropping the fluids out, the oil seemed fine, and the coolant had the very odd speck of oil in it.

Just done a cold, dry compression test, had 95, 95, 95, 102. Is this a little low or just from being cold? It has been stood for about a week as I don't want to run it until I know for sure what's wrong.

I have heard various rumours about Subaru dealerships being over cautious with the head gaskets, as well as people changing the fluids after diagnosis from them and not having any further issues. I have also heard that the head gaskets are prone to break between the oil and coolant ports at the bottom of the head.

Anyone got any advice as to where I can go from here, and if there is any other way to test without having to rip the heads off for a closer inspection as it's the DOHC.

Many thanks in advance

merlin24

iTrader: (1)

Comp test should be done with a warm engine and the throttle fully open.

Results should be between 138~160 psi with a minimum of 120 psi.


Mick

scoobyricht

iTrader: (4)

get a sniff test done to determine if combustion gases are in the coolant.

Rally_matt

Ahhh..., throttle WIDE open, ok! That could explain the low results then! Doh! Looks like i will be doing a retest. Better pop some fluids back in then :/

Should I run a wet test after to compare results? Also, Am I right in what I've read, 5ml per cylinder?

No insurance on it yet so can't take it anywhere. Are the sniff testers on eBay really as bad as people are saying or enough to get a rough idea?

Rally_matt

Thanks all for the advice.

Well, bearing in mind the motors done nearly 240k, but has been looked after by one owner, here are the results. (Started turbo corner then worked around anti clockwise.., teas nearly done and haven't time to google locations & firing orders!)

Turbo corner: 149
Power steering revs: 147
Battery corner: 146
Screenwash corner: 143

As previously stated, there were no signs of head gasket failure either from the exhaust, no bubbles in the tank, no sweet smell in exhaust, and no overheating. After the compression test (done dry but after warming up to normal op temp with FOT) im wondering if the usual oil & coolant port has got a slight crack in it? If so, if I bypassed the heater matrix first, could I get away with using some steelfix rather than rip the engine apart as it's only going to be more of a fun plaything/hill climb project?

merlin24

iTrader: (1)

Comps are better this time around

TBH, at that mileage and a possible hill climb project,I would at least pull the heads to change the gaskets let alone splitting the cases to check the mains and big end bearings.
Wouldn't be suprised to see the upper big end bearings to be worn/starting to go through Babbitt layer.

Mick

Rally_matt

True, but with limited time, budgets (due to road rallying in the festa/other projects/family) and the limited use it will get, is it worth investing that much cash & work into it along with the expense of meeting regulations? Prescott will only be 45 second runs so will have minimal usage under stress & in all fairness, the car doesn't owe me anything which is why I wouldn't mind crunching a panel or two on the Armco/tire wall as much as I would in my everyday drive or the Caterham rep! Worst case is it will eventually cost me £800 on a used engine which is a hell of a lot less work to sort and probably not far off the same money to rebuild the bottom end.

Just checked history, cam belt looks ok but is due so I will replace that & the tensioner if needed. The heads were taken off to replace gaskets, valves, stems, seals under 90k ago so theoretically it shouldn't be too bad inside and if there was an issue with the block end I'm sure the Subaru Dealership would have picked up on it while the head was off for the extra income!

Rally_matt

A bit of an update as I've now got insurance on the wrx.

Coolant and oil were drained, thermostat has been replaced and I have burped the system as best as I can. Trouble was, I could not get the fans to kick in while holding 2.5-3k so I've risked it for work today. I had done about 13 miles of A road until the temp gauge decided to rise to H. Pulled over immediately, left key at acc to keep fans running n raised bonnet to help cool.

While looking for leaks and checking levels I noticed the second fan wasn't working. Quick change of fuse sorted that out. I had a feel of the rad pipes too, top felt warm and pressurised, the bottom one was also pressurised and warm by the rad although rather cold next to the thermostat?
_
Seemed to be ok in town traffic for the last 4 miles. Once cooled down, I checked levels as the thermostat must have opened, only had about an inch top up to do?

Just returned from sniff test and it passed, has anyone else got.any ideas or had this.issue before? Could it be dodgy water pump, blockage in the two small pipes to thermostat housing, air lock or just that I haven't burped the system enough? I've added 5-5.5 UK litres to the system but can't find any leaks or damp areas anywhere. Hmmmm?????