Ok - Rolled her onto the drive (slight up hill) did two more bleeds, and took her around the block a few times. Got up to 105c but that's it.

Also checked the new water pump pulley to see if it turning - good to go there. Was worried I didn't push the tension belt tab back in.

I'm guessing it's a trapped air issue. I'll keep an eye out obviously, keep distilled water with me... PS - The way that I'm able to monitor my engine temp is through the 'hidden menu' in the tach.

 

Took her to work this morning. Still haven't made it there.
At idle car temps float around 100c -108c.
Driving under 50mph the car gets up to 120c pretty fast.
Heater is on and blowing very hot air.
Bleeder valve let's only coolant out at this point.

Please help.

 

What are normal temps?

Also fans seem to work fine.

 

On R56S = 225*F to 230* is normal.

 

Thanks. She gets up to about 253F pretty quick.
No leaks, heat works, fans work, water pumps turning, thermostat replaced in February.
Any chance this is a bad sensor in the thermostat not letting fluid circulate?

 

Update.
Took her into dealer. Mini Plano. Nice place. They flushed the system and believed it to be the coolant temp sensor. I bought one, replaced it today, still overheating.

1. New thermostat
2. New water pump
3. New coolant temp sensor (top of thermostat housing)

Here's my new guess: Radiator clogged?
The bottom hose feels cool and hard to the touch. The top hose is extremely hot.

Searched for radiator issues, came up fairly empty.

Can anyone point me in the right direction?

 

New developments.

When driving the car with the A/C on, it doesn't overheat.
I'm guessing the thermostat has a stage that opens when the A/C is engaged to help keep things a little cool?
This points me back to the thermostat as the problem.
Is it possible that it's not opening for normal driving? And only opening for harder / A/C driving?

At this point I've read too much and I can't remember where, but I thought I've heard this happening with the N14s. That it'll open a second stage or gate for sport mode or A/C?
Please say this is true. If so I'll pickup another thermostat today.

Again, thanks for any help in advance.

(Man these forums have quieted down A LOT since I was here a few years ago with my '05) Boy do I miss those days and waves.

 

Never mind.

It overheats with the A/C on as well.

Back to stumped.

Let me know what you think, guys.

Thanks again.

 

Bought and put in a new thermostat tonight (oem from the dealer $175).

Killed the battery introducing the new coolant because I let it sit too long with the fans blowing and seats heating and headlights... lighting. Recharging it now.

The old one didn't look too good... no obvious signs in my limited experience but I have a feeling it was failing. Update to come.

 

i thought you changed the thermo (8/16/16 post)? how dead did you kill the battery? if it ever slow starts you should change it to make sure you're not stuck somewhere looking for a jump start.

 

Right. Previous thermo was just installed in February. Wasn't OEM though. Figured at this point might as well put a new OEM one in to help eliminate it from the equation. I'm not convinced though honestly.

Car started right up after a short charge.

Drove around the block, got it up to 105c and quick bleed and coolant level dropped a tad. However, smoke/steam? scared me a bit and I'm calling it a night. I'm guessing it's leftovers from a boil over this morning. I'll keep filling, bleeding in the morning.

One thing I noticed I'm not sure about is the radiator pipes. One at expansion tank area is crazy hot, while the other lower hose is cool too touch... What's that mean?

Thanks for your help!

 

Update.
Cleaned up the heat shield etc from all the previously boiled over coolant and haven't seen any smoke.
Filled the expansion tank to max line, started her up, drove around the block, let out air from bleed valve and the car got up to 105c pretty fast. Even after bleed, coolant level in expansion tank rose a good 1.5" so I turned it off and came into work with the honda. *sigh
The current symptoms I noticed =
1. the 2nd stage fan never kicked on (even with a/c running and ctemp reading 105c.
2. the rad pipe near the expansion tank gets extremely hot very fast while the bottom/passenger side pipe stays cool to touch.
3. Out of the 1.5 gallons of fluid I thought the car was supposed to take, I still have about 1/4 gallon left to feed it and it's already saying it's over max in the expansion tank.

What should I look for next?
I was thinking about trying to bleed from the bottom rad hose while the car's running to see if there's just that much air trapped somewhere...

This is nuts.

Thanks for your help guys. Stick with me.

 

Your lower radiator hose is for "emergency / reserve" use --- it only flows when A/C MAX is used, or when "the pedal is on the metal". It stays cool otherwise. At least this is how my '07 works.

As for overheating, look for hoses that might be soft enough to collapse. Also, when I replaced my t'stat housing a few months ago, I switched a couple connectors and blew out the temp sensor. Ensure you have all connectors in that area connected correctly --- they are easily switched, even with the built-in "keys". Note that there's two "plug-ins" in the housing (at least on my '07MCS) --- a sensor and a heater. You mention the t'stat was replaced. How about the t'stat housing? That's where the valve is located and they're known to stick.

In spite of other indications, a compression / leak-down test might be worthwhile.

 

When you're bleeding, make sure the heater is set to max hot to flow coolant through the heater core. A/C max fan, max cold should flow water to the bottom hose and the temp should go to 90C if everything is working right.

 

Appreciate you're thoughts!
I'll recheck the two connections. Sounds like we have similar housings.

But you've got me worried. I thought the thermostat was built into the thermostat housing? Thought you had to replace both by default?

 

Max hot, for bleeding.
Max cold with fan at max for cooling down the car?! Why is that a little backwards to me?
When I turned the ac on last time I tried this, the sucker heated up super fast. It got to 105c at half a block.
With the heater on it takes a good couple miles to get it that warm.

Shouldn't the second stage fan be on at 105c?
At idle with ac on, the car reached 106c and no second fan came on.

Once home tonight I'll give it another whirl.

Thanks for your help!

 

T'stat valve is built-into the housing. Temp sensor is mounted on top. T'stat heater is mounted low in back. So, which do you want to call the "thermostat"?

 

Max cold/fan drops temp via that bottom hose you feel is cold. German engineering at its best. Normally you go from 108C to 90C in less than a minute by blasting the AC. Weird but true.

 

120C on my jcw gauge is red zone. Hope you didnt blow head gasket. But you'd probably see oil in coolant or vice versa if that happened.

 

Am I correct about the 1.5 gallons of fluid? (still have about 1/4 gallon to feed it)
I'll try bleeding with fan on max and heat on Hi. (have only ever bled with fan on low setting, Hi temp)
Shouldn't the stage 2 fan kick on if the cts is reading 105c?

Checking electrical. Here are the only two connections I could imagine getting mixed up. I've been connecting the green one into the cts, the brown one has been connected to the air near the turbo. Correct?
Tugged on the back t'stat connection - didn't come loose. I'll reconnect all of these though.



Ok great. - I call the whole housing the T'stat (since you can't replace the T'stat without replacing the housing).

I will give this a try - I've that here multiple times.

Agreed. I was worried about that as well but I see no oil in the coolant thus far.

 

Quick Update.
Disconnected & looked over the couple electrical connections.
For me at least, there was no way to swap the green and brown plugs ( I tried ).
The back one looked good - replugged it in.

Car's idling with heat on Hi, max fan speed. Blowing hot air. So far no air from T'stat bleed valve. The coolant in the expansion tank has risen a little bit very slowly.

 

Quick drive around the block. Heat still on max temp and fan.

CTS reading went from 83c to 90c pretty quick. Pulled back in the garage, opened the expansion tank cap, bled from the t'stat housing and only got coolant.

Coolant level went up another 1/4".

 

Update.

Getting no air from bleed valve, only coolant.
Heat blows realy hot.
Coolant level has risen to about a half inch above max.

For kicks, I turned on the ac max.
cts reading jumped from about 87c to 101c and a fan turned on (didn't sound like stage 2)

Turned everything off, cried a little and am currently looking for emotional food.

Thanks for any help guys.

 

As for swapping connectors --- mine is currently completely dis-assembled so I can't easily verify which one goes where. My original swap was the coolant temp sensor with the connector on the PCV port at the turbo inlet heater. Everything was all apart, I just didn't label things, and made a bad choice during re-assembly. It threw a coolant code, so if you aren't getting a code, you probably didn't make this mistake.

Are you certain your t'stat hoses are connected correctly? Could you have an input hose connected to the output? Not sure it even makes a difference --- just a SWAG!

 

I think everything's hooked up correctly. I've done it now three times. But I don't have access to a code reader.
The only code the dealer received while diagnosing it was a faulty CTS. But I've replaced that twice since then haha

Expansion tank gets super hot btw.

Should I take it to a shop, non dealer, around the corner? Have them try to flush out air...?