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overheating

2628 Views 30 Replies 7 Participants Last post by  adc
ok... so I just replaced the radiator in my ex-wifes' '01, because it cracked at the plastic-aluminum joints, and because I'm a nice mofo. But after I installed the new one, it still seems to overheat.... she's not loosing any coolant. I made sure to replace the thermostat and the radiator cap when I did it. What else could be wrong? Should I try replacing the coolant temperature sensor??? Are those known to give out at some point?
Also, is it normal for the radiator fans to only kick in when the A/C is on?? They don't seem to spin otherwise... :confused:

any ideas appreciated...
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50/50

Did you dilute the coolant to 1:1 or use a 50% pre mixed? If you used 100% concentrate the engine will overheat.
I meticulously and precisely mixed a 50:50 solution of distilled water and coolant concentrate. I mean I took an empty 1 liter water bottle, poured distilled water to the brim, did the same with the coolant in another 1 liter bottle... and poured them both into an empty coolant jug, and shook the crap out of it, and THEN poured it into the radiator. I repeated this until the radiator was full. Then I started the engine for about a minute or two with the cap off to "burp" the system, and added a little more of the mix again to capacity. It was the same thing I did in my own '01 when I replaced my head gaskets, and I've been going for over 2 months in mine with no issues. Please tell me if there's another way....

There's also a faint burning smell coming from the engine compartment.

I think that the same underlying issue may have been to blame for the original radiator failing. It might be a long shot, but is it possible that the water pump failed and is not circulating anymore???? how can I tell if this is the case without taking the timing belt off???
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Water pumps usually fail when the impeller shaft bearing goes. The pump leaks and makes a horrible noise at idle. You should first pressure check the system to locate any leaks to 15PSI. Hopefully a blown head gasket isn't allowing exhaust gases to displace coolant and overheat the engine. Unfortunately, the most common reason a Subaru engine overheats
If you look a few posts down I had the same thing on the wife's 04 (Radiator went poof!) Turned out the over heating was water pump impeller broke off and no coolant flow.
The radiator blew bc it was overheating. I'm guessing the water pump.

Kudos for taking care of the ex
Water pumps usually fail when the impeller shaft bearing goes. The pump leaks and makes a horrible noise at idle. You should first pressure check the system to locate any leaks to 15PSI. Hopefully a blown head gasket isn't allowing exhaust gases to displace coolant and overheat the engine. Unfortunately, the most common reason a Subaru engine overheats


Yeah, but she is not loosing any coolant at all.... I'm going all in with the water pump suggestion... time to get into the timing belt area. I used the Stant Thermostat on her car...some guys here are saying that one is not the best. on mine I used the Auto zone Duralast brand with no issues.... I'm thinking I should use that one again on hers...
I used the Auto zone Duralast brand with no issues.... I'm thinking I should use that one again on hers...
I use a brand name or nothing at all. On Stant they have really good quality and cheap stuff. If you use Stant request the X-act stat. It looks like an OE re-box. Brass center, larger spring and probably twice the heft.

Course my post isn't to knock your choice of parts but I have been selling parts for 30 years. A t-stat is not something I would bet my engine on. Spend the $$ and get a factory Subaru unit.
Spend the $$ and get a factory Subaru unit.
This
Well, I advised her that this radiator may crack too... so she told me go ahead and order the whole timing belt kit with water pump. I know I had issues with my tensioner pulley not working properly after I re-installed my timing belt from the HG job, and I wish that the price of the tensioner pulley alone was decent... but it's not sold anywhere for less than $90.00... why the hell is this? for about $40 more you seem to be able to get an entire kit with a water pump too??? really!??
Anyway... I ordered it just to be on the safe side... because I'm gonna check the T-stat first, to see if that's the real issue... if that's the issue, we'll just end up returning the kit... because the timing belt seems like it's been done around 100K or so.. telltale signs? timing belt cover missing a screw... and NAPA brand drive belts on the alt/PS pump pulleys.
On a side note.... AC delco sells a kit with water pump that has the same item number as the Gates kit.... SAME PRODUCT??? I figure I can trust the AC delco kit because Subaru was partially owned by GM back then... so they probably were in cahoots with each other about parts sales. plus it's cheaper too...
I'm letting her borrow my other car so she's not in a bind...but I really do all this for my son, so that he can make it to school and doctor appointments. Kids first, even after a divorce.
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I use a brand name or nothing at all. On Stant they have really good quality and cheap stuff. If you use Stant request the X-act stat. It looks like an OE re-box. Brass center, larger spring and probably twice the heft.
yeah, that's the one that I ordered... X-act stat P/N 48457... You're darn right about the weight on that thing... I had to use some clear gasket sealant around the gasket just so it would stay in place for a few seconds.. enough time to stay put when I was trying to screw in the bottom pipe attachment... SOB kept falling out into the coolant drain tub..

So you think the T-stat is probably ok then? I'm still gonna test it in some boiling water...
It may be but for the work involved and you are replacing many things I'd swap that as well. If you have your receipt it should have a "limited lifetime warranty" just explain the issues and say this may be the problem. If you come to me and explain issues and have proof of purchase I work with you.
I meticulously and precisely mixed a 50:50 solution of distilled water and coolant concentrate. I mean I took an empty 1 liter water bottle, poured distilled water to the brim, did the same with the coolant in another 1 liter bottle... and poured them both into an empty coolant jug, and shook the crap out of it, and THEN poured it into the radiator. I repeated this until the radiator was full.
FYI - Save yourself the trouble next time. Just alternate dumping in each in half gallon increments. The coolant will be well mixed within minutes of starting the car.
FYI - Save yourself the trouble next time. Just alternate dumping in each in half gallon increments. The coolant will be well mixed within minutes of starting the car.
I would like to do it your way, however, what if the last half gallon you put in is of coolant, and there is no more room to add distilled water to bring it to a desired 50/50 mix. I always want half and half... call me crazy, or just call it a personal preference, I don't care.
The way I do it, I have some left over mix that I can use either for the overflow tank, or to add back to the radiator after I "burp" the system. Worst case scenario, I've got some left over for next time, or just for top-off in between.
I always save an bottle of coolant and keep a bottle mixed 50/50. I assume you are using distilled water. Didn't mean to insult your knowledge, but just wanted to be sure. BTW I always just fill it, drive it for a few miles, let it cool, add more to the radiator and repeat. I know..PIA, but it works.
One other thing a guy at work told me about is the possibility of the radiator fans not operating at normal temperature. When I have it parked and idling, the fans are not switching on unless the A/c system is operating... is this normal given the cooler ambient temperatures in this time of year?
On my Foz, the fans do the same thing... cycle on and off only when the A/c is on. Since the fans are controlled by the Coolant temperature sensor, (am I right?). Could it be that this needs to be replaced? How can I test it for function??
I spent a good hour burping my radiator yesterday. Is it possible that the system wasn't burped properly? I've heard that subarus are notoriously hard to get all the air bubbles out of the cooling system.
When I have it parked and idling, the fans are not switching on unless the A/c system is operating... is this normal given the cooler ambient temperatures in this time of year?
On my Foz, the fans do the same thing... cycle on and off only when the A/c is on. Since the fans are controlled by the Coolant temperature sensor, (am I right?). Could it be that this needs to be replaced? How can I test it for function??
They cycle on and off..I think from 203F to 200F. If you have an OBDII you c\should see that. They will do that even without A/C on
I hate to keep bumping this, but can anyone shed more light onto the coolant temperature sensor test or a possible fan relay malfunction at normal operating temperature? .... I really want to test those while I am testing the thermostat. Thanks....
As far as fans..they will come on at I think 203F. You don't have an OBDII right? They should come on eventually even in winter at idle
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