Hello everyone, new to the forum.

Picked up a 2010 Turbo in May of last year. Currently has 35,711 miles. Passed pre-purchase inspection at dealer, found some minor things, got them fixed.

Car sat for several weeks while I was ill in December. Went out this past weekend to do the cabin air filter, and immediately got the low coolant and temperature skyrocketing on the dash.

Checked coolant level on the reservoir, the red indicator all the way over to the minus sign. Added about 1/3 gallon of distilled water, got it back to half. Drove around yesterday, got up to operating temperature, let the car sit overnight, and I've lost coolant. Indicator has moved below half a bit -- not all the way to the negative sign, but it isn't where it was so definitely have a leak somewhere.

I do not see visible spray of dried coolant anywhere. I do not know if the water pump has ever been replaced on this vehicle - only had records from CarFax. I do believe the recall with the glued in pipe has been done several years ago.

I suspect it is the plastic coolant vent line (y shaped) as discussed in this thread and this thread. (Part# 948 106 026 22)

Looking for advice. I used to have a 2000 Land Cruiser and replaced all of the cooling hoses in that, so I'm somewhat capable of wrenching myself. I've never taken an intake manifold off, but it doesn't look that hard. It's all just bolts, hoses, and clips, right?

Is this the correct order of operations?

• Get car to position in garage I can easily work on
• Remove intake manifold
• Identify where leak is coming from
• Order correct parts
• Assuming it is the vent line -- remove fuel rail, remove old coolant line, install new line and reverse previous steps
  • Any tips for removing fuel rail so I don't start a fire in my garage? (Never removed one!) Torque specs, etc.
• Install new intake manifold gaskets (does anyone have a write up?)
  • Do you need new bolts like this FCP Euro kit or can I save $130 to just get the gaskets?
• Refill with correct Zerex G40 coolant (Is this a 50/50 mix of 2 gallons?)
  • Any guides on burping the car correctly?
  • I would also buy a new reservoir cap for $10 from FCP Euro for further peace of mind

Questions:

• Do I need to disconnect the battery while doing all of this work? If so, does anything have to be reset when I reconnect the battery?
• Any other places to look for leaks before removing the intake? (I've looked as much as can down below the engine, everything is dry, don't see anything at all, which is why I suspect it is in the "V" where that plastic hose is located)
• Would a water pump leak be very obvious once intake is off?
• Anything else to replace while I have the intake off? (For example, the plastic tube that someone replaced with a brass fitting?)
• Anyone have a FSM download or step by step guide for this type of work?

Thanks in advance for your guidance!

Edit: Just@ciaka's great starter replacement thread with some of the torque values etc so that answers one of my questions

 

Following with interest , mine is the exact same , can smell coolant, it was needing topped regularly , but no puddle underneath.

 

Was the coolant changed recently? It could have air pockets in system and as the air bleeds the coolant level drops.

 

No coolant change.

Got it in May.

Got oil changed shortly thereafter.

No problems since then on spirited drives. Parked it for 3 weeks, come out to move it out of the garage for the cabin filter, coolant down. So something has to be leaking somewhere and since I can't see any bright pink anywhere, thinking it is the Y vent pipe.

I went out and backed into the garage, looked again for any signs of coolant. This is on the driver's side cylinder bank, looking down toward the valley. Could that be dry coolant blasting up from the Y pipe onto the sides? I looked (and tried to photo with camera, couldn't) under the air intake to see if there was anything pink around the water pump, but it looked fine.

My fear is this: getting it apart thinking it is the Y vent pipe, and it isn't, and now I'm on a wild goose chase, versus paying my independent and it just being done... albeit at likely a 3-5x of what it would cost if I DIYed it. I'd feel more confident if I knew what it was because there was a clearly visible leak that didn't require removing the intake manifold.

 

You can fill max level and wait to see. If necessary, you fill at max level a next time.

 

Wait and see if the leak becomes more obvious?

I can't imagine this is an air bubble in the system, I've driven ~2500 miles over 7 months and this is the first time this has happened. I have to believe there is a leak somewhere.

 

Possible. Have you remove engine protect under the car to see?

 

I have not. I don't have ramps, just jack stands. Guess I could get ramps first and take the engine protect off if I had to. Or just carefully jack it up onto my stands using this diagram (?).

Does the photo above look like coolant spray to you?

 

Coolant it's orange and it's easy to detect.

 

I had a similar issue and believe it was escaping past a hard o-ring on the cap. I bought a new cap last month and no issues since.

 

Interesting... I just ordered a new cap and an air filter for the front. Should be here in a week.

I'd be surprised to have that much coolant evaporate that quickly though. I put it right at middle, and it is now to the right of middle (like the left side of the red indicator bar is just beyond the midpoint notch right side). Seems like a lot to lose because of a cap, but considering the vehicle is 13 years old and a cap is $10 I'll give it a shot. Probably makes sense to start with the easy things first.

 

Coolant smell can be normal, depending on the car brand and model. I had a W166 MB and a couple of the hose connections (recirculation pump in the W166 case) allowed "sweating" of coolant when the engine was fully warmed up. Coolant smell is common on 2000-teens MBs. "Normal" according to MB.

Agree with replacing the coolant reservoir cap(s).

Fill the reservoir to the specified level, to establish a known good point. Then watch the level. If it decreases, you have a leak (duh! ) .

You need to be more agressive and remove the underbelly shield and any underhood engine covers, and spend time with a high intensity LED flashlight crawling all over the engine to find the leak.

If you don't find an external leak, the coolant could be exiting the tailpipe. Check for steam/fog, or a sweet smell from the tailpipe. Check for chocolate-milk sludge under the oil fill cap.

Check the piston crown (remove coil and spark plug, use high intensity LED light) for "washed" appearance. This is a sign of coolant in the combustion chamber.

 

There is a coolant pipe that plugs into the back of the thermostat housing. There are two o-rings on that fit around the pipe that were leaking on my 2014 GTS. There is no preload on the o-rings as they slip into the back of the thermostat housing. They were flat spotted and no longer sealing. Since replacing them, and coating the new ones with high temperature silicone lubricant, my coolant level in the reservoir holds steady. Had no idea this was an issue until I removed the pipe to upgrade the thermostat housing. Definitely a weak spot in the design. There was no visible coolant probably due to slowness of the leak and evaporation from high temperatures in the valley.

 

No chocolate milk under the oil fill cap when I checked a few days ago. It is really cold here, so I'm trying to wait for a warmer day to see how much exhaust comes out upon startup.

As you said, if I refill and then it goes down... coolant is coming out somewhere. I just hate the inability to see it easily. When I did the thermostat and coolant hoses on my LC, it was clear as day where it was coming out. Made diagnosing and buying parts simple. This is... befuddling. Like you said, I need to get it up on stands, remove the undercover, start looking. Just frustrating and I need to stop coughing before I really tackle this.

Yeah, and that's under the intake manifold right, so feels like if I get to that point in diagnosing, in for a penny in for a pound... committed at that point. I also hate to take it to my independent with their shop rate, but the whole cost-benefit of playing "whackamole" trying to diagnose does come into play too. Argh.

 

Not a trivial repair, fuel rail has to come out. In my case the thermostat housing was removed which helped because tube because I could not remove one of the tube support bolts near the firewall so the thermostat housing had to be pulled forward. If you don’t have the time or patience or DYI experience, a pro would be the best option. Like all modern cars, they are not designed for ease of service.

(If had to do this again, the difficult bolt would be sawed off after loosening it or I would find a way to move the electrical conduit above the bolt. The companion is more than enough to hold the tube in position. Very over designed)