Ok so for a couple of months now I've had a problem with the car missing after long drives or when using the air-conditioning, so I decided to follow the advice of a couple of posters on here and replace the O-Rings on my injectors. I did the plenum pull, and when I had it off I found that the coolant system attached to it was basically f****d. I took off a hose and the metal underneath it was so corroded that it took the end of the pipe with it. I decided to do a coolant bypass, since it seemed stupid not to, as the hoses were also cracked and leaking coolant. I removed all the lines and capped the hoses (Item 10 and 11 in the below photo, which the guide said to just cap off if you're doing the coolant bypass) and then set about putting it all back together. The Good: I got it all back together rather easily, then I took her for a 10 minute drive with the air-conditioning on 20 degrees the entire time, and it didn't miss a beat :zlove: The Bad: When I returned home and parked it up, I walked out later to find that my car had dropped an unholy amount of coolant. I noticed the coolant was coming from towards the centre of the engine at the back (somewhere around the green circle) The Weird: When checking all the hoses today around that area, tightening clamps, searching for a disconnected hose, and looking for any leaks, I decided to check how much coolant was in my radiator. I opened the cap and I could actually see the coolant sitting in there, but I would have dropped at least a litre the other night in the garage after the initial test drive. So my questions are: A) Did I miss a line somewhere? If so can you point it out to me. B) If I didn't miss a line, is it possible that this is just extra coolant that was supposed to be going into the coolant lines under the plenum? Thanks in advance.
Reservoir doing it's job If you lose coolant, when it cools down it sucks coolant from the reservoir into the radiator. Could be that bastard hose, just a little left of your circle?
"Warning Will Robinson" (metal arms flailing) Did you replace All the coolant hoses at the rear? If not you may be tempting fate as I once did. Result blown motor. Also could you have cracked one of the many pipes at the back? Hard hoses are a no no. Especially the feeds to the turbos at the hose bends. Agree with Rob260 get a pressure test done on the cooling system to put your mind at rest.
The one coming off the circular looking thing? (I'm so great with the names) Also the car is a N/A if that narrows it down at all.
As far as I can see, there's no leaks from anywhere that I was working. But that could just mean I need my eyes checked. I'll have to book it into the mechanics for a pressure test then, or learn how to do it. For now, it can live in the garage because I'm not game to drive it until I know it's fixed.
As Rob has mentioned, a pressure test is mandatory, you should have done one prior to starting the engine. The alarm bells should have been ringing when you encountered the rusted/corroded coolant lines under the plenum, a sure sign that antifreeze (rust preventative) has not been used. The downside to this is every metal pipe in the cooling system will be in a similar state. Coolant pipes also corrode/rust from the inside, therefore it is difficult to gauge the condition or serviceability based on external appearances.
I just figured the previous owner had not changed the coolant in god knows how long, when I purchased the car I put new coolant in it and the old stuff was a really dirty brown, so that should have been have been a warning too. Also please remember that I have no formal mechanical qualifications, I'm one guy working on it from my tiny shed, and I'm learning more and more about this car as I work on it, so saying things like "You should have known to do this" really doesn't have a point.
All good I don't think East Coast means any offence -he's a nice guy with a wealth of information to be mined. If you've done the deletes correctly you should be able to have the top off the plenum in under and hour and perform a pressure test to locate the leak. I always pressure test before putting the plenum back on, simply because of the time it saves If you don't have a tester they're a worthwhile investment, I can't remember what I paid for mine but I've used it that many times over... there's one here for example
Would I be able to use the same plenum gasket again? I replaced it when doing the pull last week, and I don't particularly feel like waiting on another gasket to get here. Also I just put a post on my local car page asking if anyone would lend me one for the weekend in exchange for a carton of beer. I'd consider buying one but I think I'd only get a use or two out of it before it sat in the shed for the next 5 years.
From what I have read mate I would take a wild stab at the leak coming from #11 in your picture. (not capped properly?) It has been over a decade since I completed my bypass under the plenum but I do not recall "capping" or "blocking" any of the coolant lines. I ran a continuous line from one side to the other as per an old tech write up from tt.net I think it was. I don't think any damage has taken place yet. You found it before it lost all it's coolant. It at this times seems that way Best of luck and let us know what you find
Just had a quick look at your profile, yours is a TT. If I recall the article correctly from the Z32 wiki you have to run some hose the TT (I didn't read it thorougly) but if you have an N/A it says to basically cap off the lines that go to the plenum coolant lines. Looking at the photo again I think I may have capped the hose from the wrong end, which could possibly mean that the coolant is just running freely out of where the arrow is pointed.
Ok so I took off that hose, and when I did some more mysterious brown sediment fell out of it. This time, I dumped it of the bench and out of curiosity, put a magnet over it aaaaaand it's metal. Should I just abandon ship now and sell it if I have metal jamming up my coolant pipes?
No - its not uncommon to have metal particles in your coolant given the rusty pipe situation (requiring an under plenum coolant delete) If it was in your oil or fuel - that would be a problem! But for coolant - its ok! Just flush all parts out very well - (the block / radiator and the pipes) flush out with plenty of water to get it all out (it should be clear when flushed)- there is likely to be some metal particles in any rubber hoses (where rust tends to build up) so pay particular attention to them (a squeeze and release can help it break free and release rusty / metal filled areas) If you just filled it up with new coolant - you can save it and reuse it - just use a filter to strain any small metal particles out. Metal particles in your coolant can affect the thermostat and water pump and can buildup in the radiator and pipes but otherwise won't do any significant immediate harm Brown thick coolant is normally a sign of poor circulation or a dead end pipe - not a concern based on what you have stated as you state that you may have used the wrong connection and/ or the pipes filled with crap can cause this - either way once clear or routed correctly it should be fine All is good - just flush very very well
That is NOT a good sign, especially as you have just refilled the coolant system. Here's what you need to consider: An engine that overheats is pretty serious, if it gets hot enough, it's terminal. The fact that you found rusty metal contaminants in the cooling system indicates that the system was not cleaned properly. Also there is a possibility the radiator core could contain similar material, causing restrictions & reducing the cooling capacity.
I would stress the freeze plugs (welch plugs) comment as well, if you have found that the coolant was not of the best quality and there was a lot of corrosion then these are definately worth checking,
I have the day off today so I'll have to stop off at Supercheap and buy some new coolant and give it one he'll of a flush out, it's going to be interesting what kind of nasties are in the coolant lines though.
