BRAT, diminished cooling capacity and strange fast idle..

[vorn]

Hi all,

 

Recently I purchased myself a 1989 BRAT, which I love dearly.. it had full service history, which was frequent and lavish and seemed to run fine. I gave it a good inspection, changed the oil and coolant and drove straightaway to Melbourne (2000kms from where I was).

 

Highway driving was fine, then i noticed the heat rising when i climbed a steep grade... wasn't much of a concern as it just rose above half then settled back down, but what I didn't know (should have checked) was the thermostat was faulty... so the thermo fan hasn't been running for god knows how long... it has a mechanical fan also which works fine.

 

So the other day I was driving in city traffic, and heat started climbing, and rose to about 3/4, and was close to 4/5 before I pulled over cursing and realised what was going on... I hardwired the thermo fan onto 12v and now the engine runs cool again (about 1/3) even in traffic... but just as a test, i disconnected the thermo fan and now she gets quite hot just from idling and driving around the block, and never really used to. It has also developed an abnormally fast idle sometimes, which causes the engine to shudder after being turned off, needless to say, I hate this sound.

 

There's no white smoke, and the oil seems fine (no milkshake) but the oil fill point is a tube that leads to the engine, not directly on it like other engines, so i can't say for sure what the oil looks like. It's driveable and goes fine other than the idle sometimes, but it's concerning.

 

I'm going to take it to a mechanic asap, but is it possible i've even cracked the head gasket or manifold gaskets just from a mild overheat? Is there anything I should check or change myself that may be causing the idle problem?

 

In eager anticipation... thanks guys.

[TomRhere]

Welcome to the Board!!!

 

I realize things are done differently in other Country's, but I don't recall ever hearing of a BRAT with a mechanic fan as orginal equipment.. One electric fan for non A/C, and two electric ones for A/C is the norm for the States.

 

I would swap in another thermostat, from Subaru, to begin with.

Radiator is 20 some years old, if it's the original one. Could be it's clogged up some. New one is preferred over trying to clean the one in there now.

 

A mild overheat shouldn't do any damage to the engine. As long as it was just for a short period of time. Long period of time spent with it in the Red, would be a different story.

 

There is an idle-up system on these for A/C equipped vehicles. If you have A/C, it could be the cause of the high idle, if you have the selector set for Defrost.

 

Just a few things off the top of my head there....

 

Would be nice to see pics of under the hood....

[phantomD]

BRATs (Brumbys) were standard in Australia with a crank driven mechanical fan. Also, he is not talking about the thermostat but rather the thermoswitch on the radiator. They also had a different console and selecting defrost will NOT engage the a/c.

 

For Australia-specific information I would recommend posting on http://www.ausubaru.com.

 

Answering the question, I agree that hot temperature running for a short period should not cause concern. If anything leaving that fan hard wired is OK but getting a colder thermoswitch on the radiator will help stabilise temperatures. The best setup is the twin electric fan with a colder thermoswitch as otherwise your engine temperature will fluctuate quite a bit. This setup does however put a large strain on your electrical system and you may run into trouble if you also have spotties, a/c, a decent sound system, headlights on, etc. I use a 90A alternator which eliminates these issues. Yours is overheating up hills, mine would always overheat when doing stop-start driving in bumper-to-bumper traffic, but this has disappeared with the electric fans. The mechanical fan doesn't quite cut it by itself, and the electric fan was always an emergency thing when the engine would REALLY heat up (hence the need for a colder thermoswitch with the twin electric fan setup).

Edited November 26, 2010 by phantomD

[GeneralDisorder]

The EA81 radiators are brass tank units - a good radiator shop can clean that unit up, repair any leaks etc, and have it good as new for about $50. Worth it IMO. Less than half the cost of a new one.

 

GD

[Loyale 2.7 Turbo]

I Agree with GD that the Radiator must be Clogged and it doesn't Worth to Clean it Up; but Also if I Understood Vorn's Writing well, Now his Brat's (Brumby) engine Trends to raise Hot Easier (Faster) than it used to be before the "Almost" Overheat it had...

So, if that goes along a Coolant Loss (More info needed) it could have a Head Gasket issue, Specially if he Does not Know if the Engine got Overheated with the Previous Owner...

As Suggested by GD, to Change the Old Radiator with a New one (along to the Thermoswitch) is a Very Good Idea... You can do that and watch the Coolin' Behaviour of your Subie's engine, if it still trends to run Hot, then a Head Gasket could be Worn.

Good Luck!

Kind Regards.

[vorn]

Thanks alot for the feedback guys. I've been checking and topping up coolant daily since the issues started, the temp gauge never entered the red, the temperature does stabilise and it runs ok, but a new radiator/flush sounds like a plan, along with the colder thermoswitch. (rainy days are ok, but the hot summer days really make it that much worse) There's no A/C on this model.

 

Twin electric fans sound great, but I'd have to cut the shaft off the crank fan in order to fit another one in there! The crank fan is close to useless.

 

I'll post some photos of the engine bay for those interested, I've never seen this type of setup either.

 

The rough, fast idle is the main concern now.. hopefully after a major service it'll come good.

 

Cheers!

[TomRhere]

""BRATs (Brumbys) were standard in Australia with a crank driven mechanical fan.""

 

I, did not know that. Don't recall ever reading about that setup before either.

My 1st thought when reading the opening post was, someone has swapped an EA82 engine in there.

 

Didn't know about the difference in the climate controls either.

 

I learned something.

[GeneralDisorder]

EA81T's had mechanical fans off the water pump like the EA82. In fact it's probably a very simlar water pump to the EA81T.

 

GD

[TomRhere]

EA81T's had mechanical fans off the water pump like the EA82. In fact it's probably a very simlar water pump to the EA81T.

 

GD

 

I've only seen exterior pics of a Turbo EA81 of any model, no clues to what's under the hood of one. Well besides the obvious turboed EA81.

I feel so left out........

[Ricearu]

you may also need to replace the fan clutch, if it has one. my 88 GL's mech fan clutch went out on me and did similar. To check it, warm engine up, maybe till its running a little too warm. Turn the engine off and spin the mechanical fan and see if it has much resistance. If the engine is above about half way, that clutch on the fan should have alot of resistance and should be almost locked up. The hotter the fan clutch face gets, the more grip it gives to the shaft, thus spinning the fan faster and cooling more...

[vorn]

Awesome idea - I'll check it first thing tomorrow.

 

Today I found that the fast, rough idle was caused when the velocitator pedal was depressed too far, it wouldn't come back up fully, but after i stuck my toes under it and pulled it back up, idle would come back down and settle. Over-revved while changing gears too, and could have been part of a compound problem; that is me revving the engine more to get the clutch fan spinning faster, but then going back to idle with engine revving too fast and transmission in neutral.

 

So currently, the pedal doesn't spring back to original position when released, i'll try greasing the pivot point, but can this be also caused by a bad spring?

 

Also - also also also I noticed, there is a summer/winter switch on the left hand side of the carb with two intakes, one that recirculates preheated air or one that draws cooler air from below, will check it and flip if neccessary tomorrow, as it's summer here now. I noticed all this stuff tonight, in the dim light so it's no time to start meddling...

 

Cheers for all the responses guys, I'll post some pics tomorrow because this this is immaculate for 1989, has custom bullbar and large canopy, fitted with a mattress and camping gear! Bush Brumby!

[phantomD]

Very interested to see photos of another immaculate 89 Brumby, thank you. By the way that mechanical fan has no clutch, I should have taken a photo of mine tonight (removed from the engine).

[Loyale 2.7 Turbo]

...The rough, fast idle is the main concern now.. hopefully after a major service it'll come good...

 

I Was About to Suggest to Search for Vacuum Leaks, but since you already Found that the Accelerator Pedal Does not Return all the Way up, Let me Tell you that I Had the Same Problem and I Solved it easy: Adding a Return Spring to the Accelerator at the Carburetor.

I Really will Like to See Pics of your Brumby, Specially the "Winter / Summer" Rare Switch... Sounds Very interesting.

Kind Regards.

[ajs425]

i had this same problem on my brat eventually the engine went out so im swappin in an ea82

[GeneralDisorder]

i had this same problem on my brat eventually the engine went out so im swappin in an ea82

 

That's just wrong for soooo many reasons. Stick with the EA81 or move up to an EJ. Nothing to gain with an EA82 and it won't fit right between the frame rails.

 

GD