OVERHEATING - new everything

I need help! I am at the end of my rope here. 2007 Legacy GT Limited 5EAT, roughly 130k. Car started overheating as soon as last winter ended and the weather warmed up. Threw tons of parts at it per multiple shops diagnosis (all wrong):

 

New Belts

New Water Pump

New thermostat

New Rad caps

Mishimoto WRX radiator (its huge)

Aftermarket hayden transmission cooler (i Think the 67 model?)

 

All of which was done because they guaranteed it wasnt the heads. As most of you Im sure are familiar with, I took it to a subaru specialist (has a 600hp built track subaru) who has a shop and is building these platforms left and right for people. Anyway, he diagnosed headgaskets. Soooo, I got that done, as well as a bunch of other gaskets, heads machined etc.

 

Well, weather warmed up again today (70), winter is coming to an end, and im heading up the mountain (maybe 5-6 degree incline), cruise control set, and my water temp guage starts climbing steady to 200.. then 205.. then 210.. and the temp guage on my car starts climbing.. Exactly like before! although I must say alot slower. Does anyone have any idea how an entirely new cooling system and new headgaskets couldnt fix an overheating problem going up hill or under any type of "extended" load?? I am PERPLEXED. Normally the water temp is sitting at 180 or lower just under normal conditions.. Water temp guage is hooked up to the water pump where im getting my readings btw. Some may say air bubble.. I have burped it, he has burped it, and that still leaves the question of where this air is coming in.

 

Turbo has been checked, no play, it's in surprisingly excellent shape. Oil changed regularly, transmission has new fluid, rad is full of fluid, overflow is to the full line. all of this work has been done in the last 7k miles except headgaskets... im thinking 3k. Got the car back from shop after heads the day before christmas and was running like a new car. (I drive alot)

 

I am about ready to cut my losses here.. have about $4-4500 in just this overheating situation and its still happening. Let me know if any of you have experienced this before and found a solution... much appreciated

There must be a coolant blockage somewhere. I would explore finding a diagram with all the coolant hoses and inspect them. Maybe even get an Infrared thermometer and double checking the radiator is cycling the coolant through the whole thing. Both of these suggestions can lead no where but I am not sure where to go next either given the work done already.

Heads possibly were not machined to the correct RA finish.

 

 

 

As you have had the head gaskets replaced recently, the work should be under warranty.

 

 

 

Take it right back to the shop and have them pull the heads and return to the machine shop to check them again and I sure there are no small cracks missed. Sometimes machine shops make mistakes or miss things. Nobody is perfect.

 

 

 

But this should not be at your expense. Should be a warranty issue now. Simple.

Honestly, I would say try burping it again...

I finally broke down and bought one of these funnels

 

EPAuto Spill Proof Radiator Coolant Filling Funnel Kit

https://www.amazon.com/gp/product/B01I40ZQWE

 

And it does wonders for burping the system.

You put it in your overflow tank, put a little bit of coolant in it and watch the small bubbles roll out.

I would recommend letting the engine run for 15-20 min.

I figured it had to be burped by 10 min, but was still getting tiny bubbles.

Also carefully squeeze the top radiator hose to help push out bubbles.

For me it was a little after 20 min that my last little burst of bubbles came out and it's been great since.

Found this when searching in an older thread, would make me want to look into air issues a little more in your shoes.

 

Since you noticed it when at an angle, my money is on a trapped air bubble in the system. That's the easiest and cheapest to fix, so start there.

 

-Mike Paisan

 

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https://legacygt.com/forums/showpost.php?p=4609365&postcount=8

 

Maybe try doing what Rao and AZP say in the thread below

https://legacygt.com/forums/showthread.php/burping-lgts-cooling-system-looking-reassurance-161707.html

Hey guys. Yeah gonna burp it again, maybe throw on some silicon hoses. Does anyone have a hose diagram for the cooling system? I was hoping maybe the heater core was blocked but the heat is HOT throughout the entire hill climb... like a sauna. As soon as i come over the crest of the hill, the temp drops down to half of normal operating temp. I did reach out to the shop that took care of my headgasket, gonna see what they can do for me.

 

Forgot to mention, I replaced the AC condensor infront of the radiator at the same time as the rad as that was so damaged from 100k miles of stuff flying into it. Replaced it to have as much flow as possible.

 

My only inclination of as to why is along the lines of NewEras comment. Either a blockage somewhere or the hoses are collapsing... BTW, i went out and checked and the hoses were not replaced with the new radiator... is this a facepalm or should I have gotten larger hoses when I went to the double wide radiator?

Are your fans working properly? A friend of mine was blowing radiator hoses and overheating, and it turned out to be that he had a blown fuse to the fan relay.

Here's places to start to diagnose the cooling issue:

 

If you have no percolation at the top of the system (turbo coolant tank), then head gaskets should be good. This might be of help to test to see if they are, in fact, leaking into the coolant:

 

https://www.toolsid.com/oem-tools/block-tester-mpn-27145.html?view=422545&gclid=EAIaIQobChMIscq5756F4QIVBg5pCh0DigZsEAkYBSABEgL-hPD_BwE

 

If that checks out to be OK as per instructions (you'll have to do this at the turbo tank as it's the highest point in the system), then you either have a blockage somewhere in the system or you have an air bubble somewhere and the system needs to be bled out repeatedly until there is no more air. Also, as lil'redwagon pointed out, make sure your fans are operating as they should. Fan relay could be bad too.

 

Pull the radiator and flow check it (block the bottom outlet and fill it completely with water and then release the bottom. It should completely fill the entire diameter of the bottom tube for a couple of seconds as it drains). Just because it's new and huge, doesn't mean that it's good. It could have a failure inside when they put the tanks on. If that checks out, then remove the heater hoses and plumb them together around the heater core and see if that helps.

 

Last thing I forgot to mention-are you sure the water pump impeller is still connected to the water pump shaft? I've seen that happen before (not on Subaru but on Chrysler) and you'll chase it forever trying to find the issue. There should be a LOT of movement in the radiator of fluid when it's idling.

I vote leakdown test before spending any more money on anything else. That way, you know for sure the motor is good mechanically and that the overheating issue isn't from bad machining or headgasket related.

According to the shop working on my wagon, the coolant sensor on top of the block goes bad. If so, all manner of bad stuff happens.

I read a suggestion elsewhere on this forum to jack the front-passenger side of the car to burp successfully. After overheating a few times this worked for me.

Fyi, Mishimoto radiator is no more efficient than stock. Due to losing the foam insulation and the fit of the fan shrouds they can actually work worse than stock.

 

You could have a small bubble or a solid obstruction moving through the system. The heads could be lifting, you could have a cracked head or gasket, the list is LONG.

Same thing happened in my wife's 08 OBW. It had the head gaskets done about 6 months before we bought it. After a couple thousand miles it developed an intermittent overheating problem. At the time it had roughly 120k miles on it. I tried changing the radiator because it had a tiny leak, flushed the system, burped it really well parked facing uphill and all of that, changed the thermostat with an OE Subaru stat from the dealer just in case the shop used cheap parts, did belts and hoses, checked the fans etc. I called the shop that the PO brought it to for the gaskets (dude specializes in Subarus) to see if they had the heads machined or not, and they did not, so the guy cut us a deal because even though we weren't the ones who paid for the work it was less than a year after so he said he'd re-do the head gaskets and send the heads out for machining this time and only charged us a few hundred (changed the t-belt, water pump and whatnot while he was at it). The guy drove it around all day doing errands then left it idling outside his shop for 3-4 hours with no signs of overheating before he called us to come pick it up. On the highway halfway home it boiled over again all of a sudden. Brought it back to him thinking the block was cracked or something, and after a couple days of head scratching and throwing every part imaginable at it, turns out it was simply a clogged heater core. He had a 6cyl tribeca at his shop that he was having a similar issue with that he was about to give up on, after he fixed ours he realized the tribeca was having the same problem. Turbo or not, 4 or 6cyl, I guess with the way the cooling system is routed on most Subarus it's pretty bad news to have a clogged heater core. I would not be at all surprised if that was your issue. Our heat was super hot most of the time too, only when it would start overheating would the heat cut out which lead us all to believe it was air getting into the system via headgaskets. Don't be fooled, just because the heat is blowing ungodly hot air doesn't mean that you don't have at least a partial blockage in there.

 

Long story short, try bypassing your heater core for a couple days now that it's getting warmer out. If that fixes the problem you've found your culprit. If not, light the car on fire and call it in stolen.

Thanks WOT. I had mentioned that in my post earlier too. Not seen it happen on a Subaru but have seen it on a number of American vehicles, especially if they are a vehicle with rear heat (Suburban, minivan, Excursion, etc.) and once you bypass the heater core, it let's the flow go back to the engine.

Wow guys thanks for all the replies. WOT, Im already thinking about leaving it in a high tide area and just having it flooded out lol.

 

Okay, so ill have them check the heater core and fans first as those seem to be the easiest. It will be burped regardless just as a precaution. My only question: would a bad fan relay or something along those lines really cause overheating going 70mph down the highway? I feel as though theres more air going through the rad then the fans could ever pull through on their own.

 

Will also have them check the thermostat even though its new just to make sure and as suggested pull the rad and check for blockages. If all else fails ill throw a 160 tstat in and new hoses just to cover all bases.

 

Boxkita , can you tell me more about the coolant sensor and what it does? I figured it was all mechanical in the system... coolant heats up, opens thermostat. (Sorry for my lack of knowledge here)

 

You guys are awesome. Im gonna do some more research on that mishi rad too... under normal conditions im sitting almost a notch lower than "normal" so i know its more than adequate cooling on normal driving. Drives me crazy tho, was 30 degrees today and went up a mountain road about 2 miles long, temp guage didnt budge from 170. if it was 55 degrees out, would have overheated

The coolant sensor would be used for the ecu to know when to turn on the fans and also when to add more fuel to compensate for a cold start. Should not matter when at highway speed and you can easily check the coolant temp via an OBD2 adapter.

The coolant sensor would be used for the ecu to know when to turn on the fans and also when to add more fuel to compensate for a cold start. Should not matter when at highway speed and you can easily check the coolant temp via an OBD2 adapter.

 

 

 

 

Fans should not matter (much) at highway speeds. High outdoor temps and a big hill would make a difference at those speeds. So would A/C use.

 

 

But, an obstruction definitional would effect temps at those speeds.

 

 

 

Temp sensor is just that. A sensor. ECM uses it for fan operation, cold start fueling, gauge on dash, etc. Located in coolant pipe running over the block (under the intake manifold).

Kinda out of left field here but was the coolant ever mixed with any other type of coolant?

 

What I mean is, for example, did you have blue coolant at one point then add green coolant?

Just to check, OEM Subaru thermostat?

 

Sent from my SAMSUNG-SM-N910A using Tapatalk

Jack the front of the car up as high as you can. You want the Radiator to be higher than the heater core in the system. The heater core in these car is higher than the engine when on the ground, trapping air in the system, which is bad.

 

 

Use the Burping thing that Infosecdad said to:

https://www.amazon.com/gp/product/B01I40ZQWE?tag=viglink20901-20

 

Be patient: When it's up to temp, slightly revving the engine should help get the air out.

210 degrees going uphill.... that's normal

 

If the only symptom you have is high temp (210 is not high, 230 is high. Damage occurs at 260), then there is nothing wrong with the car.

 

Does it spit coolant out the overflow ever?

Does it consume coolant?

I bought a 97 Outback with overheating problems. The shop had done a lot of work replacing the radiator, & thermostat and it still overheated. Long story short.. I bought a new OEM thermostat and the problem disappeared!

mwiener, above 210 is where the temp guage on the car starts to leave half way. I have read plenty and I know this is (somewhat) normal. My concern is that it does not stop at 210. If i have my cruise set (68 mph, 70 speed limit), the car just keeps going up and up. Because i just got the heads done, I come off it and take the exit or let it cool down before i keep going. Figured it would climb to a certain point but then hold steady.

 

What typically causes a blockage in the radiator? W about 5-8k on it, id be surprised to find theres a blockage inside - but i know anything is possible.

 

As far as flushing the heater core, does this get flushed during a typical coolant flush anyway? Or is this something independent that is flushed separately? I have had my coolant flushed 3-4 times before this whole headgasket fiasco so Im just wondering.

 

Again, thank you all for the replies! Love the subaru community and everyones commitment to helping eachother.

Didnt see those other replies - thermostat was done at a stealership so i assume it would be OEM. As far as coolant, not losing any, and overflow remains the same with little fluctuation. Before headgaskets I never lost coolant and no white smoke or milky oil, if i understand correctly exhaust gasses were getting inside the coolant heating it up/causing air pockets.

Honestly, bought this car with the intention to go stage 3 grimmspeed, but have had so many problems that I needed to fix before that.. Was almost happy to do the headgaskets and new cooling system as I was excited for a strong foundation before I start modding so that was no problem to me.

 

Now, even on flat level ground, if i do any "spirited" driving, the guage climbs as if i were going up a mountain. Im graduating school in May and will be leaving the mountains and back to flat level ground of the eastern shore, so if it were just mountains I wouldnt be concerned. However even on flat ground any type of extended boost or load and that guage is climbing. If my budget allowed I would just get rid of it and get an sti.. but am concerned about those 2.5s now. Not sure what year that problem was addressed by subaru, but i know the new stis have rod issues etc. maybe an FB20 for the win when the time comes...

 

I have pics of the headgasket job from the cylinder heads to what measurements were sent to the machine shop btw.