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Guest Message by DevFuse

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Thermostats for Comparison

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5 replies to this topic

#1 88 EA82T

88 EA82T

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Posted 23 March 2010 - 11:13 PM

I have an 88 GL10 with the stock EA82 turbo and I replaced my thermostat back in September. I took some pictures to show the difference between the one that was in my car (on the right) and OEM one I replaced it with (on the left).

The Subaru part number is 21200AA121. The big difference is the cross sectional area where coolant can pass through so the benefit would be more flow through the radiator which should improve the cooling efficiency.

I hadn't seen a direct comparison like this on the board so I thought it would be good to add...

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#2 Turbone


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Posted 24 March 2010 - 12:41 AM

The OEM thermostat has always been a recommendation here, along with the PCV unit.

#3 TahoeFerrari


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Posted 24 March 2010 - 10:06 AM

As long as same temp thermostat was used I wouldn't expect any problem, but it's probably not necessary:

Some time back I experimented with a couple of EA82s to see if they would benefit from cooler thermostats. What I found is that if the thermostat temp was reduced by more than a few degrees the ECU would think that the engine was not up to operating temp (via the output from the engine-mounted coolant temp sensor) and seemed to run the engines richer that necessary and thus clobbered gas mileage. A change back to the stock thermostat temp and the gas mileage returned to normal. I repeated the cycle twice for about a month each time with 2 different EA82's and got the same results. Note that these were NA SPFI engines, but I would expect the same with a turbo engine. I also did this during the winter/spring when daily temps were cold to cool so it might help in summer but I suspect that during colder parts of the year it could actually hurt.

#4 88 EA82T

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Posted 24 March 2010 - 10:57 AM

Yep, I installed the OEM thermostat based on the recommendations here. I also installed the proper NGK plugs and wires based on the recommendations here.

My car runs pretty good and I depend on it to commute 50 miles a day roundtrip. I am just trying to do the best I can to make my motor last since I am a little paranoid also based on what I have read here and I can't afford the downtime or the money to EJ it which is probably beyond my mechanical ability anyway. I do have an all metal radiator for an automatic installed (my car is a manual). I just need to figure out if it is a single or dual row core. My coolant temperature goes up a bit when I turn the AC on so I might need to flush or replace my radiator before it gets too hot around here.

The next couple of projects are replacing the mechanical fan with an electric one to take some stress off the engine and improve cooling and then try to find the parts to install an intercooler. I haven't had good luck with the junkyards around here to find the parts so hopefully when I get to Portland in May I can hit the u-pull it yards to find an intercooler setup...

#5 GeneralDisorder


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Posted 24 March 2010 - 12:41 PM

hopefully when I get to Portland in May I can hit the u-pull it yards to find an intercooler setup...

Not likely. I run the yards here every week and I haven't seen one in ages. Craigslist, etc would be a better bet. Or decide what model you want an IC from, find a forum for them and ask for a used one.

As far as the thermostat - it's well known that the OEM one's are better. I took a similar comparison picture and posted it..... probably 5 years ago.


#6 The Dude Abides

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Posted 24 March 2010 - 12:45 PM

As long as you replace the belt driven fan with something you will be ok. Subarus have 2 fans. The electrical fan is for the engine and the clutch type fan is for cars equiped with ac to keep them xtra cool.

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