Good morning all. I thought I would be a cool idea for me to post up my progress on my current project, I little history. So I got the car 4 years ago from a family member after he purchased it from a so called mechanic (more like bodge it and scarper) for the first year I ended up with the brake booster vacuum system coming apart (not sure this is the correct name for it but it’s the part that is strapped to the top metal coolant pipe that runs over the engine from rear to front) I ended up bodging this myself with cable ties as money was tight due to baby number 2 on the way. Next up the diverted valve this was making a “farting” sound every time you let off from WOT so that was changed with a genuine Audi part not expensive at all. When baby number 2 joined the family funds took a turn for the worst and I had to park the old girl up. She was off the road for a year and half with no starting ect. When the money situation improved I decided it was time to get her back on the road. So first thing I don’t was changed the coolant, flushed all the coolant out with clean water, reverse flowed the heater matrix then I scanned the car for any faults. The car had one fault, short to plus on the electronic thermostat.i purchased a new one from euro car parts at just under £60 fitted it but for some reason was refusing to open up and no fault codes. Now every one in this game knows that not just pattern parts but thermostats in general can be faulty strait of the shelf. So I took my original thermostat that was faulty first and took all the internals out and popped this back on the car, filled her up with coolant and took her in for her mot. SHE PASSED a couple of advisory’s which was corrosion on the brake flex and exhaust. Emmistions was spot on so much so that the garage said it wasn’t far off a new car emissions standard, I was over the moon with this. Anyways now that all that was out the way I needed to sort the thermostat out properly as it was causing the fans to come on full speed as the car didn’t know what was going on and kept throwing up EML. So got a new genuine Audi thermostat and fitted it no fault codes engine was running as it should happy days. Last year 2018 I took the mrs to work as normal which is around 20 miles round trip, I looked down and happened to glance at the temp gauge and noticed the temp needle was a smidge (very technical) over 90.c, now any one who knows there car knows when something isn’t right and I was no different. Anyways another mile or two down the road and the temp gauge kept creeping more and more till it one mark before red then big red coolant light flashing on the dash. Pulled the car over and checked the level and it was low so I opened up the expansion tanks (BIG BIG MISTAKE) and coolant came rushing back into the tank and I could hear all the pipes making noises from coolant boiling. Now a big problem with the A4 is that the water pump is made of a plastic impeller on a metal spindle and is a very well known fault for become detached and stopping flow. So I booked her in to have cam belt and water pump changed £500 later and was told the water pump they took out was not faulty but when it was last changed had been put back on the engine using a lot of sealant. They also said that when they was burping the system the cars temps hit 98.c twice and had to let it cool down both times. On the third attempt of them burping the system she was behaving herself and keeping within specs. Everything was good as far as I was concerned until I took the mrs to work again and once again it over heated. It may also be worth me mentioning that every time the car over heated all cabin heating was lost completely. So when I got the car home noticed that there was a puddle under the car and immediately thought that the water pump wasn’t sealing correctly and this could be the reason why the original work on the pump had sealant on it. So took the car back to the garage and was told it was the expansion tank releasing excess pressure from the cap. I didn’t like this answer as it didn’t seem right to me, I asked them to carry out a gas check on the coolant system and sure enough it was finally diagnosed. The head gasket has failed and the coolant leak that was thought to be excess pressure from the expansion tank has turned out to be either the J plug or thermostat (haven’t got that far yet to be fully diagnosed).
Now the garage that I take my car to is a very good friend of mine and has always helped me out with my previous Audi and said that he’s happy to do the work needed but could cost any where between £700 and £1500 depending on how it all goes.
Now the cost of the car verses the cost of repairs means nothing to me the car will have its end days with me and won’t be sold on. I have mechanical background and have decided to tackle the whole job myself win or fail.
So this thread will be updated as I go with the project or rebuilding the whole top end of the engine and finding out what the actual cause of the head gasket to fail.
So far I have purchased all the relevant Audi specialist tools from cam belt tention tool to head bolt ribe tools and everything else in between.
PHASE 1
So my first plan of action was to work out why I kept loosing my heating. Possibility in my view was with the compression from the pistons pressurising the coolant system it could be filling the coolant system with air and creating an air lock in the matrix. So to check I took the old matrix out of the car which can be done rather easily with access from under the drivers footwell. The only problem being that you have to loosen the Hvac from the car as to get the matrix past the brake and clutch pedal bracket. On removing the old matrix thought it seemed rather heavy on one side of it and decided to replace it. Purchased a new one from euro car parts as they had a discount weekend at a cost of £60 fitted it but when it came to putting the seals back on they supplied 2 lots of seals. The first set matched those that came off the car initially and the 2nd set was a set of o-ring seals. Now for the life of me I couldn’t work out where the o-ring seals was supposed to go so I left them out and fitted the same style seals that cam off the old matrix. These however was not up to the job and every time I tried to mount the pipes into the matrix the seals kept popping out the side resulting it in not sealing.
Purchased a new set of seals and clamps from Audi direct and they went on like a charm. The seal kit from Audi was only a £10 so not exactly breaking the bank and worth every penny. Decided after removing the original matrix I would cut it open and inspect and damn it was blocked by almost 50% with what looks like rad weld or equivalent so definitely worth changing it. Pictures to follow.
Bled the system and started the car just long enough to check that their was no leaks and it was working. All was good face melting heating and no leaks very happy.
PHASE 2
Now I needed to find out what part was leaking on the engine. Was it the thermostat or was it the J plug as the coolant running down the engine was definitely pointing to that area. So as I’m going to be taking the head off and also need to identify what was the cause of the head gasket failure. I’ve decided to strip as much of the coolant system as possible for investigation and cleaning. So I removed the fuel injector rail this is very easy to remove. There are 2 Allen bolts on the rail mounting to the inlet manifold and a jubilee clamp on the hose connecting to the metal pipe at the back of the engine bay. Remove those and give the rail a little wiggle lifting up and should come out nice and easy. However I recommend that before doing this you clean around the injectors and much as possible before removal as when I took mine out a lot of dust and debris flung out and some entered the inlet manifold. Not what you want if your just servicing the injectors as dirt will enter the engine and could cause massive problems. Now I have removed the injector rail I’ve removed each one and cleaned them up with brake cleaner and compressed air and they look new. However before the go back in the car they will be having a full service. You can purchase a full seal kit including the little filters that are inside the top of the injectors from a guy online called Mr Inector. Price for the rebuild service kit is around £15-20 not big bucks but definitely worth doing in my opinion if your removing them anyways.
Next remove the metal coolant pipe that runs over the top of the engine also known as the coolant return feed. On this pipe you will have to remove the front rubber coolant pipe their are two more underneath it which feed to the thermostat and the oil cooler and one at the back from the coolant manifold on the back of the engine. These are easy enough to remove but may be a little stuck like mine was. I found getting a blunt object and sliding it in between the metal and rubber joins is the way to get them free enough to pull off. The biggest problem I faced on removal of this pipe was the rear rubber hose from the coolant manifold as the metal pin on the pipe restricts how much you can move the clamp in the first place. Going forward I will invest in a clamp tool that holds the clamp open while you remove the rubber hose.
I have since cleaned up the ends of the metal coolant pipe as they had a lot of build up ready for a coat with some temp paint to go on soon and all that was needed was 180 grit sand paper and some paitaints pictures also to follow.
So this is the story up till now. I realise this may be pointless to some of you but if some one in my position wishes to do the same sort of task it may help. As I continue to do the build I will try and be as detailed as I can. Speak to you all soon
Now the garage that I take my car to is a very good friend of mine and has always helped me out with my previous Audi and said that he’s happy to do the work needed but could cost any where between £700 and £1500 depending on how it all goes.
Now the cost of the car verses the cost of repairs means nothing to me the car will have its end days with me and won’t be sold on. I have mechanical background and have decided to tackle the whole job myself win or fail.
So this thread will be updated as I go with the project or rebuilding the whole top end of the engine and finding out what the actual cause of the head gasket to fail.
So far I have purchased all the relevant Audi specialist tools from cam belt tention tool to head bolt ribe tools and everything else in between.
PHASE 1
So my first plan of action was to work out why I kept loosing my heating. Possibility in my view was with the compression from the pistons pressurising the coolant system it could be filling the coolant system with air and creating an air lock in the matrix. So to check I took the old matrix out of the car which can be done rather easily with access from under the drivers footwell. The only problem being that you have to loosen the Hvac from the car as to get the matrix past the brake and clutch pedal bracket. On removing the old matrix thought it seemed rather heavy on one side of it and decided to replace it. Purchased a new one from euro car parts as they had a discount weekend at a cost of £60 fitted it but when it came to putting the seals back on they supplied 2 lots of seals. The first set matched those that came off the car initially and the 2nd set was a set of o-ring seals. Now for the life of me I couldn’t work out where the o-ring seals was supposed to go so I left them out and fitted the same style seals that cam off the old matrix. These however was not up to the job and every time I tried to mount the pipes into the matrix the seals kept popping out the side resulting it in not sealing.
Purchased a new set of seals and clamps from Audi direct and they went on like a charm. The seal kit from Audi was only a £10 so not exactly breaking the bank and worth every penny. Decided after removing the original matrix I would cut it open and inspect and damn it was blocked by almost 50% with what looks like rad weld or equivalent so definitely worth changing it. Pictures to follow.
Bled the system and started the car just long enough to check that their was no leaks and it was working. All was good face melting heating and no leaks very happy.
PHASE 2
Now I needed to find out what part was leaking on the engine. Was it the thermostat or was it the J plug as the coolant running down the engine was definitely pointing to that area. So as I’m going to be taking the head off and also need to identify what was the cause of the head gasket failure. I’ve decided to strip as much of the coolant system as possible for investigation and cleaning. So I removed the fuel injector rail this is very easy to remove. There are 2 Allen bolts on the rail mounting to the inlet manifold and a jubilee clamp on the hose connecting to the metal pipe at the back of the engine bay. Remove those and give the rail a little wiggle lifting up and should come out nice and easy. However I recommend that before doing this you clean around the injectors and much as possible before removal as when I took mine out a lot of dust and debris flung out and some entered the inlet manifold. Not what you want if your just servicing the injectors as dirt will enter the engine and could cause massive problems. Now I have removed the injector rail I’ve removed each one and cleaned them up with brake cleaner and compressed air and they look new. However before the go back in the car they will be having a full service. You can purchase a full seal kit including the little filters that are inside the top of the injectors from a guy online called Mr Inector. Price for the rebuild service kit is around £15-20 not big bucks but definitely worth doing in my opinion if your removing them anyways.
Next remove the metal coolant pipe that runs over the top of the engine also known as the coolant return feed. On this pipe you will have to remove the front rubber coolant pipe their are two more underneath it which feed to the thermostat and the oil cooler and one at the back from the coolant manifold on the back of the engine. These are easy enough to remove but may be a little stuck like mine was. I found getting a blunt object and sliding it in between the metal and rubber joins is the way to get them free enough to pull off. The biggest problem I faced on removal of this pipe was the rear rubber hose from the coolant manifold as the metal pin on the pipe restricts how much you can move the clamp in the first place. Going forward I will invest in a clamp tool that holds the clamp open while you remove the rubber hose.
I have since cleaned up the ends of the metal coolant pipe as they had a lot of build up ready for a coat with some temp paint to go on soon and all that was needed was 180 grit sand paper and some paitaints pictures also to follow.
So this is the story up till now. I realise this may be pointless to some of you but if some one in my position wishes to do the same sort of task it may help. As I continue to do the build I will try and be as detailed as I can. Speak to you all soon
this pipe has also been upgraded from audi and is part number 2 on my diagram. Part number 3 which comes from the bottom nipple on the purge valve to the inlet manifold was replaced with just some regular old pipe i had laying around at the time of bodging my purge valve and so i will be replacing that with a genuine one from Audi.
