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Hi im new to this site. Just wondering if someone could help me. My subaru Lseries
Wagon just started overheating about to weeks ago. So far
Iv tryed taking out thermostat. And iv flushed radiator
All so cleaned it with rods so i dont think its blocked.
Dont no what else to do now. Any help is really appreciated.

Hi and Welcome Ben james

I'd check/flush out your heater core. I'd also recommend you refit a thermostat, as this can cause your coolant to flow too fast through your radiator and not allow the fins to take away the heat. This will cause hot water to return to the engine and over heat the engine even more. I'd also check that your radiator cap is working correctly. If the cap doesn't hold pressure, your engine will boil at a lower temp.

Hey mate are you losing water/coolant?
If you just have water in it, I'd add some coolant concentrate, that way you can smell it when it leaks out and easier to spot when leaking.
Also when refilling make sure all air is bled out of the system.

I had a overheating problem with my L series that plagued me for a long time, in the end it was the radiator, even though everything pointed to that the radiator wasn't the problem.

I then bought a brand new radiator off of ebay for < $150, best thing i ever did to the car, after that it never went up past 1/3 on the temp gauge.

Buy a new radiator cap as a first step

The way I'd go with this:

Try a new radiator cap.

Try a new thermostat.

Replace water pump.

Replace radiator.

If all of the above fails I'd be replacing the head gaskets...

Or just skip to the last one if you're suspect on them. Also don't underestimate a partially blocked radiator - it'll be fine in winter then crap out in summer

Cheers

Bennie

hi again took car to mechanic he sed it was viscous fan coupling so I replaced it. fixed it for about a week and now its over heating again. the temp gage sits just above half way but only if im on freeway if im just driving around back streets its fine. I took radiator out and stuck rod thru radiator core. so I don't think its the radiator. only thing I have not tried is replacing the water pump. were dose the temp gage sit as my mechanic rec its normal to sit around half way. iv all so replaced temp sender. another thing is the car started over heating not long after I got the rear muffler removed don't no if that would have any thing to do with it tho. and it back fires sum thing shocking.

all so is it normal for the car to tick after I torn it off or is this a part of the car overheating.

The ticking is theengine cooling down mate,
Is the engine standard, do you have the right spark plugs, is it timed correctly, do the radiator hoses suck closed when hot, are you using the best coolant, is there a coolant/water leak, have you got the correct radiator, is teh fan actually working, what's the engine oil like?
Now for the most overlooked is there anything obstructing airflow through the grill to the radiator?

"took a rod out and stuck it through the core"?????
Does that mean you removed the tanks and cleaned each core?
Unless you did that, it is not a proper check/clean.
Mechanics can only assume, unless they know every detail, then it becomes a suggestion.
Without being fully $$$$ tested, it could be anything.
From what you are saying it realy sounds like a blocked radiator or could be a combustion leak somewhere, but start with radiator/cores/blocked fins.

another good question is the ambient temp at the time. If the day is 10 degrees C hotter than normal, it is gonna run a bit hotter on the gauge. These normally will run about 1/3 along the temp gauge IF everything ios working correctly in your 20+ year old beast.

I finds a good water pump test is to pull a heater hose off from the back of the inlet manifold - off the longest metal pipe comes from drivers side. Start it up and see how well the water/coolant pours out of the metal pipe. If it runs like a healthy garden hose - pump is usually good.

I am having trouble with the concept that you were able to rod your radiator core, yet had to take it to a mechanic to tell you it was the viscous coupling on the fan. Did you replace it with new or used coupling ?

I'm about to chuck a coupling coz it runs fan hard all the time, though not locked up, it never settled down, drank more fuel , probably as a result.

Now gone electric, it runs warmer around the streets.

Digital temp units such as found on ebay for as little as 14 bucks are great.

My L wagon temp gauge is always a bit above halfway. Possibly as much as 3/4 mark and the engine is not overheating. That's just where it sits.

I'd like to know what you mean by 'overheating' ?
If you didn't know that engines 'tick' as they cool down how do you know it's 'overheating' ?

hi thanks for replies. yes I took off tanks and cleaned each core using the oil dip stick out of the car as my rod lol as I couldn't find any thing else to use. I replaced it with a used coupling from Subaru parts. thay sed it was tested be for being removed from car. other thing is the electric thermo fan doesn't kick in at all so I wired it up to a on off switch but when I torn fan on the car seems to get even hoter. and when I torn it off the temp drops just a bit but fast. don't no why the fan would make it hoter. all so what is a combustion leak and how do I look for it.

Fan not working won't help matters. Did you just work that out ?
When you made the on/off switch maybe you have the wires around the wrong way and it's blowing hot air from the engine toward the rad. ?

I found my rad cap had a small leak through the rivet in the middle so I replaced it.

What do you mean by 'overheating' ? Under what driving conditions ?

Ben james wrote:... all so what is a combustion leak and how do I look for it.

good question.

Wow! I only ever ripped those end tanks off and made a mess 3 times out of four, maybe 5 out of six. How'd you do it and get them back on to seal ??

Is your reserve copping pressure and water/coolant from the radiator.

I have found Nulon radiator flush to be effective to clean crud out, not to resolve overheating, though I flush things clean first, then add it for the 20 - 60 minute drive, flush,flush.
Combustion leak may be pressure leaking from combustion chamber due to head gasket leak or crack in head and there is a sniffer device rad shops and some good mechanics use to sniff out combustion gasses in the coolant while running.
Was the weather cooler for the week after you replaced the viscous coupling (with a similar aged one)

steptoe wrote:Wow! I only ever ripped those end tanks off and made a mess 3 times out of four, maybe 5 out of six. How'd you do it and get them back on to seal ??

Use rachet straps to get the end tanks back on under pressure, then fold up the little tabs to secure end tanks. Install and check for leaks. Done.

Ben james wrote:the electric thermo fan doesn't kick in at all so I wired it up to a on off switch but when I turn fan on the car seems to get even hoter. and when I turn it off the temp drops just a bit but fast. don't no why the fan would make it hoter. all so what is a combustion leak and how do I look for it.

Is your engine really overheating or are you just reading the factory gauge? These factory dash gauges are an indicator only, some read high, some read low, some play up and the sender needs replacing. Get an aftermarket gauge to get a more accurate reading.

I'd also check/replace your thermostat too - that could be creating all sorts of issues if it's not working properly.

Cheers

Bennie

So how's progress Ben James, it's been 4 days mate.

One thing I'm contemplating doing with the temp gauge & especially the fuel gauge is to disconnect them! Primarily because (my theory) when they are connected they are prone to identify problems, e.g. increased temperature, out of fuel etc. Therefore if we have no gauges we have no problem. No temperature increase & we will never run out of fuel.

I reckon the petrol companies are having a lend of us & that if it were not for the guages (they own) which are in all cars and are directly linked to the major fuel company IT systems, we'd never have to fill the cars up again, Try it guys we may be onto something..................or not