Thermostat and Thermo "Fan" Switch

[Sapper 157]

Ok so I have a 84 GL Wagon, standard tranny. I have read to use a 180 degree thermostat but wanted a second opinion. Also, the sensor that controls the electric fan -commonly called the thermo switch or fan switch- may need to be replaced and i was wondering if i could get a lower temp switch so the fan would turn on before the engine gets super hot. This way it can start cooling down before its so hot that it will take forever to cool. Opinions? thoughts?

 

[Crazyeights]

You really should use a factory thermostat if this is an EA series engine. It is worth the extra cost and difficulty spent getting it. I would check that the radiator isn't plugged up (if you aren't sure, then it probably is).  Also sure the fan switch works. 

Edited September 11, 2014 by Crazyeights

[Sapper 157]

Thanks for responding crazyeights, but why should I get a factory thermostat when I could pick up one at my local auto parts store for a lot less? Do the factory ones last longer?

[jj421]

Aftermarket thermostats for Subarus frequently start sticking open or close within a few months of installing it. You'll be lucky if you get an aftermarket one that works as it should. If you're on the side of the road with an overheating car, go for it. It'll get you home. But otherwise, go with an OEM Subaru one from the dealership.

[Sapper 157]

So is this a common issue in all subies or just in the older gen ones? 

[jj421]

As far as I know, it's primarily just the EA series engines. That being said, I spent $40 at the dealership for a thermostat and seal for my '93 Impreza. My personal view is the cooling system that you should get quality parts, for any car. Better hoses, OEM thermostats, Japanese made water pumps (for Subarus; I recommend the brand Aisin), etc. It's worth the extra money.

 

But I digress. As far as the thermostat goes, definitely spend the extra $$$ and get it from the dealership.

 

Also, in regards to the thermoswitch, I don't know if you necessarily need to get a new one. My EA82 has the original one (AFAIK) and it's 284K miles old. Still working fine. If someone else says otherwise, listen to them. I'm not super familiar with EA81s so my advice may not be super credible. I'm not sure about the EA81 engines, but I believe people have swapped in a thermoswitch from a Toyota or Nissan that turns on at a lower temp. Don't remember any details, but I recall reading about it last year or something.

Edited September 12, 2014 by jj421

[Sapper 157]

Ok thanks for the info.

[Sapper 157]

I know this is off the original topic but figured I would just ask it here instead of creating another thread. Okay so my question is, what is everyones opinion on using full synthetic oil instead of conventional (specifically in older motors)? I have heard great things about Synthetic and was wondering what yall's opinion on the matter was. What I have heard is that it makes your engine last much longer and it is just overall better than conventional. Thoughts? 

[naru]

I use it in my turbo car because of its ability to tolerate high temperatures,but,I think it is a waste of money for non turbos.

You would be better off using the extra cash to do more frequent conventional  oil changes,IMO.

 

Synthetic oil gets contaminated just as quickly as conventional so don`t bother w/extended change intervals.

[jj421]

Here's my opinion:

 

Use what the car manufacturer recommends you to use. They put it in the owner's manual (or on the oil fill cap) for a reason.

 

Synthetic is great if you have a new or freshly rebuilt engine. However, on a car this old, I would not put anything but conventional in. Synthetic oil is "superior" because it has additives in it that will clean sludge and protect your engine. However, on an engine this old, the sludge is actually preventing it from leaking. Synthetic oil can clean the sludge which will increase your oil leaks. There is no difference in the viscosity or flow rate between conventional and synthetic, but you may notice more oil leaks when switching to synthetic.

 

If anything, rebuild the engine first. Clean up the internals really well and put new seals on just about everything. Then run synthetic. But to me, that's a lot of work for not much gain. And besides, the engine rebuild alone will make it last longer.

 

You can always run a high mileage oil (they are part-synthetics). It's a good medium, and it's designed for older engines. But it's still got cleaning additives that can make your oil leaks bigger.

 

With synthetic, I still wouldn't go much longer between oil changes. As stated above, in these engines it doesn't last much longer anyways. NEW engines are designed to go WAY longer between oil changes, but that's because they were designed that way. Our engines are not.

 

I would say put the money in a good oil brand and oil filter. You'll notice better performance and longevity with certain oils and filters. But what's a good brand is entirely personal preference. My Subarus like Castrol GTX 10w-30 with a Bosch oil filter. I've tried a couple brands and that's what they like the most.

 

Finally, if you want to clean out your internals, put ATF in the oil. Right before your next oil change, pour a quart of global ATF into the oil. Drive about 50-100 miles then change the oil with the engine hot.

[Sapper 157]

Ok so I took your guys advice and got a factory thermo for $24.

[rdweninger]

When / If you add ATF to your engine oil just prior to changing the oil .... I would only run the motor for maybe 5-10 minutes at 1500-2000 rpm.  And I maybe do this every 3rd oil change.   I use Delo 10-40 since 1990 and I have 280,000 on my '85.   I have never had any issues with the motor, cams, valves, HG's, mains, oil pump.    I have a small cam seal leak, and if I were to put in synthetic oil, it would become a BIG seal leak. 

Compare your old thermostat to your new OEM thermostat.   You will see the difference.

Pull the thermoswitch from the radiator and clean the green stuff off sensor (inside) and the electrical contacts.   You can test with a multimeter, hot water and thermometer on your stovetop.   It will complete the ground (ie., the circuit) when it reaches 180 degrees or so.   And yes... hot water will burn you.  Ask me how I know.

You in Stanley?  

[Sapper 157]

Try putting stopleak in the oil it might take care of your cam seal leak. I put some in mine and it cleared up all my minor oil leaks (front main, oil pump, oil filter area) and im running 10w 30 full synthetic. I also put it in my transmission and it stopped a pretty bad tranny leak. maybe worth a shot. 

No I'm in Warm Lake area. 

Edited September 17, 2014 by Sapper 157

[Sapper 157]

And by the way im not 100% sure I know what you mean when you say ATF. I always thought that stood for Automatic Transmission  Fluid? so what exactly do you mean when you say ATF? 

[MilesFox]

I have no problems using synthetic. If you do, you will want to use a 10w30, 10w40, 15w40 as summer weight, and for winter 10w30, 10w40, 5w40, or 0w40.

 

What's important with synthetic is using one without too low of a zinc content. A typical 5w20 or 5w30 has 600 or 800 ZDDP, where a high mileage blend (mobil super) of the same weight will have ZDDP of 1000. Same with mobil1 high mileage. 1000 zddp is typical of a 40 wt oil, such as 10w40, mobil1 0w40, and higher with diesel oil 1200 and 1300 such as mobil delvac super 1300 15w40 or synthetic turbo diesel 5w40.

 

Either way conventional, synth, or semi, use a 40 wt il, and only use 30 wt for winter near or below freezing temps. 5w30 is not recommended. 

 

There is some truth to the myth that synthetic oils may cause leaks, as stated above as it washes out carbon which may be keeping a seal blocked up. But also, the high mileage flavors have seal conditioners to help rejuvenate tired seals. It never hurts to replace seals. And with mobil1 in their terms, they recommend addressing any consumption or leak issues befire using the product. 

 

I am running Mobil1 0w40 euro blend in 96 impreza 185,000 mi, 98 forester 2.2 swapped with 260,000mi on the engine, and a 98 legacy outback ej25d with 134,000 mi. I am going for a 10,000 mi drain with a high capacity filter. I'll make the 10,000 mi decision based on the oil at 5,000 mi and 7,500 mi. I would expect to top up a quart between 3,000 mi as a general rule.

 

Of course i am not afraid to fix a seal if it leaks. But i also work in an oil shop and see plenty examples of old and new cars and their oil conditions and what happens if oil runs low, runs overdue for service, etc. The biggest difference i see is what type of engine or vehicle determines the condition of the oil, when comparing the same oil brand and viscosity across different vehicles, or the same type of vehicles with different drain schedules or habits. 

 

As far as removing sludge before using synthetic, the ATF in the crank is good, Seafoam in the crank is good, or even kerosene or any over the counter engine flush treatments. But is the myth is true about synthetics unclgging leaks, then the myth holds true for these treatments as well. I personally wouldn't be afraid of leaks developing, or if you do have leaks, it's routine service fix it properly.

 

In regards to synthetic fluids, i installed synthetic 75w90 in the diffs in 2 of these cars, and full syn multi vehicle ATF (dextron VI) in the legacy. I do have a diff leak, but this was a pior condition, for which i would top off the same. I save rolling resistance and drain intervals which offsets my cost per mile over conventional fluids.

[Sapper 157]

Wow thanks fox! that was a lot of very helpful info. currently I am running 10W-30 Quaker State brand, full synthetic oil in mine with a FRAM ultra premium filter. the slight oil leak I had on the front main and oil pump have cleared up since i put in some stopleak.

 

Ok so this would be a great question for you: I just redid my tranny oil about a month ago. I read online that I should use 75W-90 Gear lube oil. I was rummaging through my Chilton repair manual for info on the rear differential tonight when I stumbled across a section which said to use 85W-90 gear lube. So my question is, Do I have to redo my gear lube again or is it ok to run 75W in my tranny?

[rdweninger]

Sapper, I think what you are talking about are two different things.    The rear diff has gear oil.   Drain and replace the fluid.

Then, the transmission has it's own gear oil.  Drain and replace that.

I think I used 80w-90 in both areas... or maybe 75w-90.  

ATF is automatic transmission fluid.   We use it as a 'cleaner' in our crankcase (and other fluids work, see above).    I remember a product called Rislone about 20 years ago.   A lot of mechanics advised it's use... but it would remain in the crankcase for the full oil change cycle.   The oil galleys in these motors seem to 'gunk up'

   I had a stuck valve in an 1800cc a few years back.   I put in ATF and ran for 6-8 minutes at 1500-2000 rpm.    This fixed the problem.   So now, just before every other oil change, I put in a half quart of ATF... run the motor for 5 minutes at 1500 rpm... drain the oil... replace the filter... fill with Delo 15-40.    I have never heard the tick of death since then.   285,000 miles.

  You do any sledding over there?   I'm ready.

[MilesFox]

for gear oil its 90 grade, GL-5 spec. The viscosity modifiers give it 80w90, 75w90. The lower the "w" number, the easier cold flow is until it warms up to 90 grade. Typically 80w90 is conventional and 75w90 is synthetic, which both are appropriate.

 

In the manual trans itself, you want to use a synchromesh oil such as subaru extra s or equivalent. This is particular to subaru since it has brass synchros, AND the front diff is part of the transmission body. The GL-5 spec is necessary for the front diff ring and pinion as any differential, but the oil must also be compatible with synchromesh.

 

A straight gear oil or synthetic may cause shifting problems. make sure whatever gl-5 spec 80w90 or 75w90 also is labelled for synchromesh as well. 

[Sapper 157]

Ok thanks rd and fox. Fox, how do I check to see if the 75w stuff is compatible with synchromesh? will it say on the bottle? And yes the gear oil I have in the tranny right now is GL-5 spec. no shifting problems

 

here is what it says about the oil i bought:

 

Super Tech 75W-90 Syn-Blend Gear Oil is formulated with conventional and synthetic base oils to provide superior gear protection over a wide range of operating and ambient temperatures. Made with premium extreme pressure additives, rust preventatives, and antifoam additives, this oil protects hypoid gears, manual transmissions, gearboxes, passenger car and light truck conventional differentials, transmission and steering gears.

Super Tech 75W-90 Syn-Blend Gear Oil, 1 Quart:

• Formulated with 100 percent synthetic base oils
• Provides superior gear protection
• Made with premium extreme pressure additives, rust preventatives and antifoam additives
• Meets API GL-5 and MT-1, MACK GO-J, SAE J2360 and Top Off of Limited Slip specifications
• Model# WM7590PL
• Made in the USA

 

 

Does all that sound ok to you?  as in, I shouldnt need to replace my tranny oil again

Edited September 18, 2014 by Sapper 157