For a little while now I've had a coolant leak from the top of my radiator that I've just kept an eye on and added coolant while needed. I've been aware that I have to replace it but being a broke college student. Not that easy. Plus it's been very cold out here so the temp stayed normal. Driving home I noticed my temp gauge rising and sitting at about middle (I have a series 4 and this is way above normal) I pulled into my driveway turned it off and popped the hood.

My overflow tank was making a gurgling noise and so was the engine... Possibly because of boiling coolant? Which is odd because I'm running a premixed 50/50.
I let it cool down a bit and turned it back on to pull it down my driveway.

No white smoke out of the exhaust. No hesitation to start. Just coolant buzzer and that's it.

The gurgling sound is what's bothering me... How would I know if I messed something up bad? And yes I'm ordering a new alum radiator as well as silicone hoses tonight

 

Leaks only came out of the front which is where the radiator and overflow obviously are

 

might have just been low on coolant and the system was "burping" itself rather violently

 

the symptoms do point to a failing coolant seal but i would probably recommend replacing the radiator cap and clean the seating surfaces first.

 

The radiator is leaking from here though. Not possible that when I turned my car off it sucked in air and made the gurgling sound? I'm going to order a radiator and hoses and go from there

 

gurgling can be boiling in the system or it can be air being pushed into the overflow tank. if the overflow tank is getting just air from the radiator that's usually the sign i look for for failing coolant seals, as air has to come from somewhere.

if there is no air being pushed into the overflow and just the cooling system is gurgling internally then find a radiator and stop driving the car. an air pocket can cause overheating issues and cause failures just as easily as age.

 

You are entitled to one overheat.

1/2 to 2/3 on the s4 gauge is not terrible. It's getting hot, but it won't kill you. Fortunately for you, you were able to shut it down.

 

About middle on an S4 gauge is only around 90 degrees. Not even close to overheating. 90 degree is lower than I typically set cooling fan turn on points.

If you have any leaks in your cooling system, the boiling temperature is much lower due to lack of pressure. So you will get all kinds of gurgling and boiling as hot spots form and the bubbles make their way through the system.

Fix all the leaks, then see what happens. If there is any doubt, an overnight pressure test will show internal leaks (and find many external ones!).

 

90 degrees in Canada is 194 degrees for us yankees.

 

Alright thanks guys! I feel much better now.
A lot less worried now hahaha. But I think it's better I leave my car parked up now until my radiator comes in

 

I have a question, btw which relates to cooling system. I have s4 turbo 5 speed with around 50k on the engine. Whatnever I switch gear at 5-6,000 rpm I get a puff of white smoke out of the exhaust. Is that seals going out in the engine? Or just bad air fuel ratio?

 

Do you have cats? Or straight through exhaust? And how thick is the white smoke

Do you have coolant missing without any visible leaks?

 

I believe I do have a cat, and as far as coolant leaks I have one by the thermostat housing and possibly at the water pump, which I'm in the process of fixing at the moment.

I should also mention that my air fuel ratio gauge is mostly at lean when I'm cruising. Not sure if rotarys run at 14.7 or leaner

 

Cruising it should lean out. I've hit as high as 16:1 and it's fine. Only in vacuum though! Anything above that it will start to stumble and be a very unhappy engine.

 

Maybe you should retune your car. To my knowledge your car shouldn't be that lean while driving and should rich out while shifting

 

the smog pump will raise the AFR by 2-3 points, so 15-17:1 AFR while cruising at lower RPMs is perfectly normal. above about 3k RPMs though the air gets dumped into the cat so the O2 sensor won't be reading it and the numbers will drop down to what is actually being burned by the engine.

but puffs of white smoke on shifts is usually oil seals or the turbo. if the trailing plugs are dry of oil then it is more likely the turbo.

 

I haven't checked my plugs yet and I do know that I need to do a tune up. I guess I'll have to fix my coolant leak and a tune up and than focus on the seals. Thanks anyway guys.

 

I just ordered myself an R series koyo rad. Thoughts on them? I've heard good things and bad things about them. I ordered via THmotorsports. Not eBay or some weird fake website

 

Rad and hoses are in. Gonna finish bleeding the system but everything else looks good!

 

and put the fan back on.

 

Yea I put the fan back on but left the shroud off to check for leaks

 

Stock fan doesn't work without the shroud.

 

Doesn't seem like I really need it right now. It's so cold out my temp gauge is staying 1/4. But the shroud is really that important?

 

if you don't mind losing about 80% of the fan's efficiency, then yes it is that important. especially since the cooling system has already been taxed several times already you don't want to push your luck.