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atlas2l8v 24-07-2019 07:11 PM

Updated - Still overpressurising
 
Updated

I have put a new cooling route in place now basic with no heater and the original stat as the picture.

My car warms up nicely, fans kick in and radiator gets hot, coolant is constantly circulating back into the bottle nicely...no leaks (I used a pressure kit and it held pressure).. it still blows through the cap.

I'm using a corsa header tank which was half full with coolant, is this too much to account for the expansion? Or the cap not rated enough psi or possibly adding an expansion tank

https://i.imgur.com/9bmV70P.jpg

Hoosier 24-07-2019 07:14 PM

No idea about the stat im afraid.
Is the rad getting hot?
When it head gasgeted, did oil get into the cooling system?
Heater inside still woking/whilst bleeding the system?

atlas2l8v 24-07-2019 09:40 PM

Quote:

Originally Posted by Hoosier (Post 16555625)
No idea about the stat im afraid.
Is the rad getting hot?
When it head gasgeted, did oil get into the cooling system?
Heater inside still woking/whilst bleeding the system?

Cheers for the reply.

Rich (Ricola) has confirmed it was plumbed in the right way, no oil in coolant, heater lines arent getting hot and no coolant coming through (ive got a bleed valve in the line)

Hoosier 24-07-2019 09:49 PM

What year and what engine?
How many bleed screws have you got on the car?
You sure the heater isnt blocked?
That can cause over presurising (not over heating though).

atlas2l8v 24-07-2019 09:55 PM

Quote:

Originally Posted by Hoosier (Post 16555655)
What year and what engine?
How many bleed screws have you got on the car?
You sure the heater isnt blocked?
That can cause over presurising (not over heating though).

Ej251 engine (2500cc non turbo) 2000 year
Ive got bleed screws (1 on matrix line, 1 on top hose at radiator)
My mistake its over pressuring as its blowing the coolant out the cap

Think i will remove my heater and check the matrix isnt blocked, plus Rich mentioned the diameter pipes on the returns from heater etc maybe to big

Hoosier 24-07-2019 10:02 PM

Is the main radiator getting hot?
If not, id be looking at the water pump.

Big Al 25-07-2019 12:14 AM

I've had a bloody nightmare with heater matrix!!! First fitted a lotus Elise matrix and leaked at the matrix and slightly at the engine tho I coukd never find the source. Decided the lotus matrix was duff and replaced with a Chinese out the box thing off ebay. I drove 1 mile to the mot station to find my engine boiling water pissing out of it seemed everywhere!!!!
I cut it out, spliced the lines at the mot station and an instant fix. Have since cut the pipes back to the engine bay and looped and touch wood no blow off in the engine bay today at least. I don't need a heater anyway.....now air con...

I don't know why but it seems the subaru heater matrix must be a higher flow rate or run at a lower pressure than matrix from other cars.

Pull the pipes off the matrix, splice together with a bit of pipe and see if have the same problem. At least will rule out the matrix if continues.

Not sure if it's my setip but it does take a good 15 minutes to get up to temperature sat on the drive. Don't expect boiling rads quickly that way. Should feel the bottom rubber hose outlet from pump getting warm first.

Again because of my unique design I have air bleeds fitted at the rad, at the matrix when had it installed but found just filling the engine a bit fruitless. I actually removed the top pipe on the matrix (mine was high up front under the bonnet) and using a funnel filled it till it overflowed. I did the same for the rad which in mine is horizontal in the back, then lastly to the engone. I'm guessing yours may be similar but matrix and rads in reverse positions.

atlas2l8v 31-07-2019 08:30 PM

Thread updated on the first post

eugopnosaj 05-08-2019 07:58 AM

The subaru engines are unique in the fact that the stat allows for the matrix to get warm before the main rad - I guess they thought people wanted to have instant heat into the cabin. When I plumbed mine in I used the original matrix, the AC matrix (refitted to attach to hoses) and now currently a heater unit from a classic mini, coupled with the subaru fan and a 4 stage switch from a Golf! Blows beautifully however it is currently disconnected as I as using the heater valve from a Ford Puma which allowed me to use a propriatary board like Ricola, but it is plastic and the rubber hose kept squashing the fittings as I tightened them causing it to leak, plus I only use it over summer so who needs it!

The subaru cooling system is also designed not to use a closed pressurised system - the standard is just basically the overflow to the expansion tank which isn't very big - I ditched the subaru one and used a classic mini one which is tiny and tucks up into the wing - my rad is at the back currently. The tank also needs to sit lower than the radiator. I've got a large "race" spec aluminium subaru radiator which has a bleed valve built in to the bottom so I use that when I fill it and I've never had any issues thus far. Not sure if any of that helps?


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