why is my 99 forester overheating???tried new thermostat..

The 2.5 liter engines are known to have head gasket issues. We have owned two over the years and both needed the gaskets once the cars hit over 120,000 miles. expect to pay $1000 -$1800 at a good shop.

Me 3...

Subaru KING of head gasket. Fails... decades worth shame on OLD Fuji Heavy Industries..

okay.. well, first thing to ask is, did you burp the system correctly? It's very easy to allow air into the system while you have the radiator off (other question) or this, changing the thermostat. ALSO, very important, which thermostat did you put in? This is SERIOUSLY important. Any air in the system might allow it to overheat.. that doesn't mean you have a HG failure. If your HG is failed, you'll likely have lava coolant boiling up into the reservoir because of exhaust gases escaping the HG. There's no shame here cuz I never knew this stuff until doing the research and we've had our subies for like 3-4 years. I am not really a fan of the additives (other question). And as far as coolant types go, there's a lot of research out there.. iirc you def want to stay away from the dexcool? chrysler stuff - right? I think I've been running prestone and I always buy concentrate and mix myself (always use distilled water). I have two links for you :: ONE:: http://www.subaruforester.org/vbulletin/f88/prestone- yellow-extended-life-antifreeze-coolant-74346/ :::: AND TWO::: https://allwheeldriveauto.com/subaru-head-gaskets-problems- explained-part-ii/ ::::: keep in touch

burp?????

Excuse you....

I'm working on a link...

Yeah, burp / bleed air out of the system. Here's a funnel I bought a few weeks ago but I haven't used it yet. :: www.amazon.com/dp/B00A6AS6LY/ref=sr_ph ::: and then here's one quick rundown on bleeding the system ::: http://strongforsubaru.com/resources/subaru-coolant-bleeding/ ::: and I've seen where people remove a sensor or a bolt out of the top of the engine or intake and it allows you to fill the coolant enough to where it comes out of that hole and then you reinstall the bolt. This gets rid of a lot of air. I just gotta find it.

it started out running lil hotter than normal one day it was like 90 degrees outside so i just thought maybe cuz of that opened hood and top radiator hose was collapsed so i opened cap a lil and hose went back to normal so i changed cap seemed better for a day then it heated up again did not overheat just hotter than normal i felt like only one side of radiator was warm so i tried spraying water with hose in it and the seam busted wide open on top radiator now junk ordered new one im just hoping that was problem and not head gaskets...when i bought car i noticed copper flakes in overflow tank so i figured they added additive as i know subarus are known for head gasket problems...i put like 3000 miles on it b 4 this problem started..the radiator breaking was my fault i know that..it only heated up on hills and when i came down other side would put in neutral and coast and it would cool right down didnt heat up idling either...just really really hoping it isnt head gaskets....radiator will b here in couple of days is there anything special i should do when replacing it????

From what I've read, you want to keep the radiator system sealed after properly filling it and bleeding the air out. And to only add fluid via the overflow / plastic reservoir. Yes, additives were added via Subaru directives to "fix" HG issues. I, personally, don't like stop leak additives and won't add anything to the system from now on in my own Sub's. It isn't a perfect solution and has the chance to block stuff you don't want to block. Hey man, we all make mistakes and I'll be honest, it takes a lot to admit to a mistake. There's a couple things you can look for as far as your HG's go.. look on the bottom of the engine on each side. Look for green/dark droplets holding on to the bottom of bolts and along the HG line (also look for dark wet lines. Don't freak out about HG issues btw... When I got one/both of ours, I was doing a lot of reading and getting seriously stressed. You can honestly go quite a while with weeping HG's.. as I have for 3-4 years and PO's have for however long. Be aware, but don't stress out. My 03 is weeping coolant from at least one HG but I also had a bad rad cap and I was losing a ton of fluid. Now, I'm not. I still drive it but I'm always conscious of the temp. So continue to watch your temp. The absolute last thing you want to do is overheat and it sounds like you were on the way to overheating. So it's ran good for 3k miles and is there any chance you looked at the coolant level in the plastic res during that time? If it ran too low for too long, it might have taken in air into the engine and once air gets trapped up inside the engine is when it gets hot "locally" and doesn't cool internally in certain places. Also, out of curiosity, 99 was kind of an odd year I think, is yours DOHC or SOHC? One poster says it's good to fill the top rad hose first as far up as possible, then connect it, then fill via the rad cap. You can also lift the engine or park on a hill with the front end up. Here's another link (disregard the angry bits, lol, still good info) :::: http://www.rs25.com/forums/f190/116363-proper-way- burp-your-coolant-system-2.html

And let me clarify, weeping will vary / YMMV. Clean oil and coolant will not degrade the gasket like bad fluids will in a boxer engine. And I still need to know exactly which thermostat you used. There are some aftermarket ones that will work and there are some that will hinder the engine cooling and it sounds like you might have the wrong one. Here's a good read:: http://www.subaruoutback.org/forums/66-problems- maintenance/11265-subaru-thermostat-vs-market-stat.html ::: and here's some Tstat part # stuff:::: http://legacygt.com/forums/showthread.php/oem-thermostat- aftermarketi-201729.html?t=201729 :::

Another good read:: http://legacygt.com/forums/showthread.php/coolant-brands- 46625.html

the thermostat i put in was from local auto parts store probably junk...i read a forum that said to use oem thermos..i have one of those on its way with my radiator...so u think would b ok to use antifreeze i just bought if i put subarus conditioner in it as i have a bottle of it...just found out previous owner put k&w bock and gasket repair in it said it wasnt leaking or overheating he put it in as preventitive because he heard of the head gasket issues with subarus wondering if maybe that is what screwed everything up??hoping new radiator and thermo cures it cuz cannot afford head gasket fix...and how do i know if i have all ofair out of system??i just ordered the filling funnel that is supposed to eliminate air in system..ordered it from amazon $ 25.00

good deal. yeah, basically, try to get as much air out as possible initially, read the links I posted above that talk about the steps to bleeding your system. The car will do the rest while running and you are helping it along by squeezing the hoses, etc. Then you'll close the system with the rad cap (also, you want to avoid the flip-top-lock deal rad cap -- they're junk). The Tstats don't look too far apart between good and bad but the good ones have the small pin on the side and they're deeper and compress more? I guess is the way to think of it. So they technically allow more flow. I ordered a Gates 34012 (because I had tons of gates stuff in my RockAuto.com order already) and it looks exactly like the oem unit. The stant 48457 looks the same, too and was talked about in one of those links I posted. The tStat works for 98-13 so disregard my 03 search -- compare pics here: http://www.rockauto.com/en/catalog/subaru,2003,forester,2.5l+h 4,1411041,cooling+system,thermostat,2200

Also, while you have the radiator out, go ahead and pull the 3? 10mm bolts off the drivers side timing cover, pull the cover and inspect your timing belt. How many miles on your forester? And do you know anything about the history of it's maintenance? ..... And regarding the first four responses about bad HG's.. did you guys get enough ear-full of non-HG talk to stop telling everyone Sub sucks and has crappy HG's? People come here (and other sites that are non-forum related) for help.. not more stress. Start asking more questions and stop blaming Sub..

Phew! This is a lot of prose! LOTS of folks replaced t-stats and rads when first-gen 2.5i DOHC motors breached the too-small HG area between the combustion chamber and coolant passage...thus percolating the fluid. (The overnight contraction of these exhaust gases trapped in the coolant is what collapses the upper hose, btw.) But there IS a SMALL chance that you simply have an insufficiently-purged cooling system. So install your new OE t-Stat and rad, and fill it. Drive a bit and then refill rad (and the upper hose), and 2/3 fill the overflow. Drive for an hour or overnight, and check again, adding coolant-mix until all air is gone. If necessary tip the car UP in front to fill the rear heater box hoses. If you NEVER seem to purge all air then remove the rear heater hoses to make sure they're not plugged (important...maybe do first?). If still no success then have radiator sniffed for HC in the percolating exhaust gases. If positive, dump the motor, as it's too old to successfully be rebuilt. Trust me on this: the newer SOHC 2.5i take HG re-sealing routinely, as these are ATMOSPHERIC HG losses. The earlier (fancier) DOHC 2.5i's HG failures are high pressure, usually with severe stressing of their blocks. Rebuilds of these older motors are rarely successful longterm. So STOP spending money until you are done with the process outlined above. Good luck, history shows the odds are against you. Sorry.

will definitley check timing belt as i know that on these motors if belt goes so does everything else pretty shitty design if u ask me...dont have much info on car history...i dont understand why subaru still uses composite head gaskets when fel pro upgraded them to a multi layered gasket seems to me they would rather put a better product out there instead of JUNK...or maybe thats there plan so u have to spend more$..just dont make sense to me but what the hell do i know obviously not much..this forum has been huge help in gathering info..thanks to all who replied..im sure i will be back on here in few days when parts arrive..stay tuned thanks everyone...

oh and walth on your other question about DOHC or SOHC im not sure but when i pull timing belt cover i should be able to tell right???

Wylde...you're not listening. reread my post and adhere to it. If you can't tell the diff between the SOHC and DOHC from outside in 3 seconds you need more help than you realize!

Look at your motor, from the front, the timing belt cover for SOHC has one circle on each side whereas the DOHC has two circles on each side (one on top of the other). It'll make sense when you look at it. No offense Ern, but you didn't explain that.. and I think it's safe to assume that he's new to subaru's? And I'm really hoping his has the SOHC.. but you've commented in the past that some 99's actually got DOHC's. So, we'll see what happens.

actually im not new to subarus this is like my 5th one my first one was an 81 it was the best one i had...i also have a 97 outback right now never had problem with it except routine maintenance like ball joints cv joints etc...but this overheating issue is driving me frikin nuts.....gonna have more $ into it than its worth...grrrrrrr

ha, oh okay.. well, just make sure when you get to installing and bleeding the system, you're well versed with all the steps and patient with the process. Ern gave you a good list to work with as well. The car does take care of some of that air, too. That's why the res isn't sealed. If you find it's too much, feel free to drop it off at my house ;P

just pulled rad it is SOHC i thought u meant circles stamped into plastic not actually molded around cam...is that good news????

for you, yes, that's great news. Keep us posted when you get the rad installed and the system bled. You won't know if your overheating issue is HG related until you drive it.. the load on the engine is what you need to test it.

SOHC 2.5i tend to initially leak coolant at #4 cyl corner, sometimes additionally leaking OIL on the opposite (right) head later. Only rarely does the HG compromise proceed to INTERNAL combustion pressure loss such that they percolate like the more flawed design of the earlier DOHC. Hence resealing SOHCs is usually safe, as perhaps very few overheating stressful events have occurred. But if you've overheated ANY block it's critical that you have the heads pressure-tested and replaned if necessary before while replacing HGs. New head bolts are a good idea. If the WP doesn't leak you can ignore it; check t-belt pulleys while in there too. Frankly, if the rad and coolant passage clean-out doesn't eliminate percolation then I would NOT spend $1.5k on a reseal on a 17 yr old...especially a wonky Forester. Fingers crossed, indeed....

good news good news put new radiator and stant thermo in today and i also bought one of those lile spill free funnel they work great i did what you guy said i filled top hose then used funnel let run 15 to 20 mins was suprised how much air actually in system...just got back from runnin the piss out of it on some pretty steep mt. roads here...gauge never left halfway mark..."knock on wood"..i also noticed that the thermostat i bought and put in last week did not have that little check valve thingy ha ha ...wtched a video on you tube guy knows his shit about suby's he drilled couple holes around diameter of thermo said that if head gasket was bad that that would allow gases and air out i just drilled 1 hole cuz the stant thermo had that lil check valve but so far so good.....im now wondering if that car quest thermo was why it overheated...not sure but it was getting warmer than usual with the factory thermo in it also..but when i changed top hose and put the car quest thermo in it it got even hotter almost overheated....i still am not overruling that it may be bad head gaskets...but like i said so far so good...fingers crossed..thank you guys so much for the helpful info it really helped me alot cant ever stop learning i sure learned a lil this week...thanks again this forum has lots of good info.....

Sigh...the odds are greatly against ya: many folks have tried bleeding the t-stat, but that only marginally slows the percolation, as it proceeds despite a wide-open t-stat anyway. So making the closed (cold) t-stat a bit porous just slightly slows the opening curve. Sorry....

u think it is HG ...couldnt it possibly be that i got air in system when i changed top rad hose??

Thank you for responding wylde9.. I'm not as informed as Ern on this matter. I'd personally just keep driving it and watching the res for lava bubbling coolant or bubbles in general and the smell of hydrocarbons. And as always, feel free to chime in with updates as I stay subscribed to 99.9% of the questions I partake in.

what does it smell like???

hyrdrocarbons? like fuel? or the smell of burnt coolant on the engine (a very sweet smell)?

Yes to the top hose! And I forgot that you have a SOHC. So let's keep fingers crossed. Exhaust gases would have very little odor, as the motor runs quite clean. Yet a HC sniffer will pick up low levels of course.

yeah that is my next purchase..have to say that i was impressed with the lisle spill free funnel worked great..never realized how much air there could be in a coolant system...and my fingers are definitley crossed as i know the HG issue is a big problem with suby's..if i had money enough right now i would just have it done along with timing belt and pulleys..have a few medical issues right now tapping me dry..my forester is one of the cleanest 99's ive seen i bought it from original owner who always had it garage kept not a speck of rust on it has 160,000 miles on it so its probably about do..my 97 outback has 270,000 on it and never had a problem with it and that one is DOHC go figure right...thanks again for all the help hopefully im not on her in a week posting bad news...

I bought ALL new hoses, timing belt kit, head bolts, two front belts, complete engine gasket kit (the DNJ iirc) and probably some other stuff and I tallied $508 for each of my engines. I don't know if that included shipping but I am happy to pay $508 and do it myself. I could message you my entire order from RockAuto. Just inspect the timing belt and as long as the idler bearings don't start letting go and the belt doesn't get fatigued, you can wait until that 105k interval (200-210ish). Also learn about the timing belt tensioner and how to slowly compress it, put a drill bit or other super hard metal to hold it until you're ready to pull the pin. I got kits with the tensioner.

i looked at the kits on rock auto def very reasonable..its the labor that would kill me..would do myself but dont have a garage anymore sorry to say we had a huge explosion in our last april and i regretfully have to say i lost my dad in that explosion..in fact im on my way to go service a REAL car now it was his pride n joy a 1957 crysler imperial with a 392 HEMI in it..yeah its got a HEMI...goin to drive in parade this weekend in honor of him...sure do miss em..anyways no engine hoist not too mention it suks doin job like that in my driveway...and dont really trust any local mechanics around here...we'll see how long the overheating issue is solved first i guess...wish me luck oh i forgot u already did...lol..thanks again...

STILL RUNNING!!!!!!!!!!!! NO OVERHEATING ISSUES.....FINGERS ARE STILL CROSSED...

Great...looks like you may have dodged a bullet.

its been smokin hot for 2 weeks...and been climbin some steep hills around here in the catskill mts....but they are still crossed...