Overheating!
 

Hi everybody, new 2 this site, just got a SVX (1992), bought it with an overheating problem (got it well cheap!)
Right symptoms- Idles fine! 30mph fine! 40mph fine! Gentle 60mph Temp goes up a bit! Floor it - temp climbs into the red - boiling in the expansion tank!
I have read some of the previous threads on here, & seem 2 have the same or similar trouble as 'ilsegretosvx' so presuming need a new thermostat & a good flush out! (fingers crossed!) B4 i think about the head gasket being done!
1st question is - Where the F is the thermostat? Had a quick look & thought it was near the rear right of the engine in that water jacket looking bit under the inlet manifold? Rang a Subaru dealer & they hadn't seen an svx for a while, had lost their book, but thought it was near the water pump?
HELP!
Phil,
Salisbury,
UK.

First, hello and welcome Phil
 

Thanks for stopping in.:)

The t-stat is located down low in a housing on the engine where the lower radiator hose enters the water pump. Remove two bolts that retain the housing and there it is.

EG33's (the Subaru nomenclature for the SVX lump) usually runs very stable temps, per the factory guage. I would recommend replacing the t-stat, and seeing if it helps. I'd also recommend a hydrocarbon test on the coolant to determine if a headgasket is shot. Does the coolant reservoir have any black gunk in it? Does the coolant smell of anything other than coolant?

I'm one of the lucky :rolleyes: ones to have lost a headgasket. No damage to the heads of block, but the gasket got weak and failed. Pulled the engine and replaced them myself.

Good luck and I hope your problem is the t-stat. If not, Joe (svxistentialist) who is located just outside of Dublin may be willing to sell you an engine.

Regards,
Todd

Thanks Todd, will take a look!
Phil.

OK, had a look tonight, got a new t'stat, but found a new 1 already in there! a small amount of gunk is in the expansion tank, but that looks like a the 'dog doo' type of rad weld!?! Refitted the t'stat that was in there, refilled with water, & ran up; took a while 2 warm up then the temp guage shot up to 1/2 way & stayed there! Checked the expansion tank was ok, top of rad was HOT but bottom hose was warmish, then the expansion tank started to bubble so i switched it off! :(
I'll do the hydrocarbon test if i can get it to work, but i think it's going to be a head gasket now!?!
Is it a hard job 2 pull the engine out?

Phil.

You should go ahead and install your new thermostat before resorting to drastic measures. I'd take the temperature differential between the hoses as an indication that the thermostat now in place isn't opening as it should.

dcb

I would also flush the radiator. If sealant was used to try to stop a leak it usually ends up in the overflow tank plugging the hole to it.

That happened to mine. The coolant could get into the container fine but the hole turned into a 1 way valve and nearly prevented the coolant from returning to the radiator.

The tank overflowed and I got coolant on the front tire...not good when you're running an autocross at the time.

overheating
 

The SVX radiator is about 60 tubes. I just had mine dissasembled and found about 20 plugged. That was enough to cause slight overheating climbing a hill with the AC on. The AC would shut off. The radiator rodding out was pretty successful, two remain plugged. No more overheating now. This radiator has about 100000 miles. The original radiator was replaced at 85000 miles for pretty much the same thing. I should have kept it but didn't realize a nylon tank radiator could be rodded out. If you see gunk in your expansion tank, I would bet your radiator is plugged because of lack of distilled water and or good antifreeze. When you drain the coolant, leave a 1/8 inch or so in the pan and allow it to evaporate. If the residue is little soft granules, that is the silicates the antifreeze is supposed to prevent. Change your brand and or use distilled water.
Hope this helps

Ok guys, will give those a go 1st, did sort of think the rad might have been blocked? will give it a flush out & see what happens next!?! lol
Phil :)

bubbling like that usually means headgaskets, and do be honest those symptomes sound like my legacy. Up to a certain mph it was alright (i sure it was overheating but the gauge is poopy) after that threshold it shot up too quick, just like you said. Pulling an engine isnt TOO hard, you might be able to do the hg's with the engine still in the car though. Depends on how much clearance there is. At anyrate, a hydrocarbon test would be best, and good luck.

Ok, pulled the rad out 2day & back flushed it, no gunk coming out, seems 2 flow ok!

Right, stupid question time! If i run it WITHOUT the t'stat, it will flow ALL the water round the system!

Now, as there is such a temp difference between the top & bottom of the rad, top being HOT & the bottom being cool, i think that as the water in the rad can't circulate cos the t'stat is shut, its not letting the water in the rad mix cos its virtually stationary & therefore NOT letting the t'stat open! cos it cant get hot enough at the bottom!

I think its a bit odd having the stat at the bottom - heat rising etc!

SO, the w/pump is swilling the cool water around the bottom of the system, while the water is at the top boiling up cos it cant move, & then it finds its way 2 the expansion tank cos its the only way out!

Does this make any sense?

I know if u remove the stat, it'll slow down the flow around the system, but at least it's flowing properly ALL the way round the whole system!

Phil

How hard is it 2 pull the engine?

The pump pulls the water from the thermostat - so it will pull anything in the radiator through - hot or cold. Hot coolant enters from the engine at the top of the radiator and cools as it passes through then goes through the t-stat and water pump and back into the engine to get some more heat.

As long as the thermostat is operating properly there is no need to remove it - it may actually increase engine temps without it due to the flow being unregulated the coolant won't stay in the passages in the engine long enough to pull the heat from it. The coolant itself would be cooler, but the engine would run hot.
I got a C in thermodynamics - someone else could probably explain it better. :)

My svx is in a similar state. Bubbling in the radiator. Expansion tank overfills after driving. No sign of oil in antifreeze or vice-versa. I replaced the thermostat, flushed the radiator, tried some liquid head gasket. I even swapped radiators between both svx's to check if one was plugged.
I have finally accepted that the head gasket is leaking.

I bought a used engine from Todd - wawazat?? to put in.

Notall- It is quite possible the thermostat is bad, stuck closed. Not letting anything circulate. It's also as equally possible one or both of your hg's are blown. If you remove the tstat yes it will allow the coolant to flow through the whole system. It'll also not allow it to warm up as fast or stay warm. Sure you say cooler engine = more power. While that is true internal combustion engines are designed to run within a temp range. If it's not in the range it wont perform as well. You can try replacing that first, which is what I would've done (and did do :)).

Immortal- Bad headgaskets don't always have the same symptomes. Some leak between the oil/coolant passages and the exterior of the gasket, some between the coolant and oil passages, and some between the coolant passages and combustion chamber seal/ring thingy (which was the case in my failure. My oil was as oily as could be, no mixing of the coolant and oil. What was mixing however was the coolant and exhaust. It was slowly blowing past the combustion seal into the coolant passages. It's not all that uncommon in open deck subaru engines. Infact it's the reason why ea81's ea82's an er27's have a closed deck design.

Ok, thanks guys, is there any way i can test the t'stat?

Can i put it in a kettle or pan of water & boil up the water! It says 78 degrees C on it, so boiling it in water should open it! Correct?

Phil.

Just tested the stat by putting it in a pan of water & boiling it, opened up fine!

Headgaskets then?

Phil.