So as of late my lovely g35x has been showing signs of slight coolant loss. I've been checking my overflow regularly and every day after I drive it I swear it's a little low.

So I decided to toss some uv dye in it and take a look around after work and I found nothing. Which sucks because either I'm crazy or I have a small head gasket leak.

I then swung past the dealership (shocker) to grab an oem rad cap and results are still pending (first day driving it after installing it). Spoke to the tech and he told me wait until you see it the overflow completely empty then bring it in. At least that way your sure it's definitely disappearing.

So my dilemma is this, theres a buddy of mines that has a pretty mint 2008 a4 he's willing to trade me with (he knows the issues). I can trade and be done with the car (rather not I really like it).

I can perform a pressure test and a leakdown test to confirm these issues. I'll still be able to trade it (he's gonna toss another motor in it) or I can let it sit and do a swap myself in the spring. Don't have the time at the moment, been dealing with family and health issues so it'll have to if this was the issue.

Luckily my commute to work is only 19 min and if I wanted to I could just keep refilling the coolant.

Also no overheating, no milkshake and I did a head gasket sniff test a month or so ago and it passed.

So what do you guys think?

 

Wait until you have the results of the coolant pressure test and the leakdown test. You might be getting all worked up over something really simple. Did you keep the old cap? I would definitely pressure test it.

If you are venting off STEAM you probably aren't going to pick up anything with the UV dye. This can definitely happen with a cap leak.

As for the A4, Audi makes some pretty solid vehicles, I like them, both my brothers are Audi guys and have had great luck with their vehicles, both the B7 and B8 chassis, granted they were driving S4 and not the A4 but the chassis is good. The only real complaint I would have is they're even more expensive to buy parts for than the Nissans,

Which platform is it, a B7 or B8? 2008 was a model change year, if it's a B8 platform with the 2.0 TSFI engine I'd say hell yeah do the trade, that motor can take some serious abuse and a simple tune gains pretty substantial power of about 50 ft/lbs torque. The earlier generation 2.0t was a very bulletproof engine with lots of performance mods as well but it typically requires actual parts to be changed before it makes big gains, an exhaust/intercooler/fuel pump/tune is like 50 hp and 100 ft/lbs torque.

 

Yes I have the old cap and as usual I have a bit of a problem over worrying about things as of late. The audi is a b8 and I've heard good things about them as well.

Question though, can I just rent the pressure tester locally?

 

Yeah or if you bring your cap down there they will probably just test it for free. Most shops will rent the pressure tester for really cheap but there's a refundable deposit you have to leave with them.

 

Autozone wants 200 plus to rent it lol. I guess it's worth it since I need to confirm the issues. They also have an adapter set that can be rented as well.

 

What the ****? Call around, there's gotta be someone that will do that for 1/4 that price.

EDIT: Are you sure that $200 wasn't the deposit? Holy **** man you can BUY the tester for less than that lol.

 

No it's just the deposit, sorry for not clarifying lol.

Also I've heard sloshing water on startups in the morning as well now that I think about it.

Air in system can cause coolant loss?

 

OK so both of my rad caps (caps I bought in the past) are slowly losing pressure according to the kit. Waiting for car to cool down so I can text the system and the new rad cap from the dealer

Edit.

Oem cap showed no leaks, tested system but couldn't build pressure due to air leaking at the pipe the radiator cap attaches to. I was using cap number 9 in the powerbuilt cooling system pressure tester kit.

Upon further inspection I noticed that the pipe opening has seen better better days

Could vapor be escaping from a poorly sealing coolant pipe?

Is the adapter that I'm using the wrong one? (just checked it says for nissan)

Also now that I think back to yesterday I was attempting to use my lisle spill free funnel to eliminate the possibility of air in the system and it started leaking from the rad cap adapter. Did the same today as well. Didn't do that beforehand. Coincidence? Hmmm

 

Visit your local Radiator shop, have them do a pressure test to pin point your leak! Cost is minimal and they'll find the issue within minutes and have the knowledge to fix the problem!
Gary

 

That's exactly what I plan on doing this week

 

Now to find a reputable one in my area

 

Update, just left a highly rated shop in the area and they informed me that it they performed the pressure test and they saw that the lower radiator hose was leaking. Doesn't make to much sense to me being though I've checked this car up and down and ever noticed a leak externally. So I got home and did some looking myself and saw no signs of a leak but I did see that the lower hose had a cut in it due to it leaning on the ac compressor so I'm assuming that is where the leak may be originating from. Just odd that I never saw drips or stains or anything

 

If it's coming out as steam it's never going to leave drips or stains. Really common, system will hold pressure up to say 10psi but when it's hot there's JUST ENOUGH of a leak that it can't hold the 15psi that it normally operates at and the coolant comes out in such a small volume that it either evaporates before becoming a droplet OR it only leaks out extra pressure when the engine is actually under load going down the road so it's not leaving droplets when you park.

 

Now this explanation makes perfect sense lol. Thanks cleric ☺

 

Update!

So I finally found the leak lol

Upper bolt for the thermostat lol, it's leaking directly from the bolt itself. I tightened it a bit more in hopes that it will stop the leak. If you've read my previous threads you'll know my disdain for the thermostat housing lol. Noticed a green soaked spot under the car and it lead me to this. So I can keep adding coolant till the spring and swap a new block in or I can just sell it like I previously planned. I think i can maybe remove the bolt and put some rtv in the hole and that might patch it up but ya never know. Swap would be easier and more cost effective but selling it would be the easiest.

Well at least it's not the head gasket lol