The radiator is one of the basic components of any water-cooled car. It is basic in another sense in that it is quite simple--it's a metal rectangle full of tubes and fins through which engine coolant flows.
A radiator, or its hoses, sometimes needs to be replaced. In the Audi A4 this is a relatively simple job, with only a few tricks to it. In the photos below, the radiator support is in the service position. Note, however, that this does not need to be the case in order to do this project. It will make access to some components a bit more difficult, but certainly not impossible.
If you're replacing the radiator hoses, all you need to do first is drain the coolant. If you are replacing the radiator, drain the coolant and then remove the bumper. Refer to the service position project for instructions on this, as well as on moving the power steering cooler loop out of the way. Removing the radiator has other benefits. If you need to access the front of the engine, having the radiator out of the way is a big help.
Let's start with the upper radiator hose. Just in front of the engine's intake manifold, this hose connects to a black pipe. Note the corresponding marks on the hose and the pipe to indicate the proper orientation.
On the radiator side, the upper radiator hose connection is a bit different. Lift this metal clip up using a screwdriver and then pull the hose straight off of the radiator. Don't twist the hose to remove it; notches inside the hose interlock with the radiator's pipe
Moving to the bottom of the radiator, you need to remove this electrical connection. It's a bit hard to reach it, but once you can get your hand on it, squeeze the ribbed top and bottom to release the connector and then pull it straight away from the radiator.
Now you can remove the lower radiator hose. Like the radiator side of the upper hose, this has a similar metal clip holding it on, except this one comes in from the side instead of from the top. Again, you can release the clip using a screwdriver. The other end of this hose attaches at the thermostat housing; see the water pump and thermostat replacement project for more detail.
It can be hard to find enough leverage to pull the lower hose off, but it can be done; it may be more difficult with the radiator support panel in the standard position. Like the upper hose, this connection has notches that will prevent it from turning, so don't try to twist the hose in order to loosen it. You can wiggle it, but mostly just pull it straight away from the radiator.
Despite the fact that you have probably already drained the coolant from every possible outlet, there will still be coolant in the system, and it will come out when you remove the lower hose. If you've moved underneath the car to remove this hose, remember that you have been warned!
OK, if you are truly removing the radiator, and not just moving it out of the way, and your car is equipped with air conditioning, you'll need to remove the A/C
condenser from the front of the radiator. It is attached by four bolts, two on the passenger side ...
Lift the radiator up and out of the holes in the support panel and you can either remove it entirely, or swing it out of the way if the
condenser is still attached to the front. As you can see here, many of the accessory belts are now with easy reach. You can also get a sense of how much coolant remained in the radiator when I removed it! Reverse the steps to put this all back together, or to install your new parts. Refer to the coolant change project for more on flushing and refilling the cooling system.
Followup from the Pelican Staff: Thanks for the follow up. We appreciate it.
- Nick at Pelican Parts
Comments: wow !need to go back to the beginning on that one! changing all of the hoses .....didn't show any of them ! come on , you guys need help writing this stuff ? people go to this site for information, and your site provides very little of that. so on to search someplace else.
January 4, 2014
Followup from the Pelican Staff: Thanks for the feedback. If we get the chance to create an article for all of the rubber hoses we will. - Nick at Pelican Parts
Comments: Your instructions are terrific but incomplete. The radiator also has two ATF transmission lines connections on the radiator side. They were nearly impossible to remove. If they aren't removed, the radiator will not come out.
October 11, 2013
Followup from the Pelican Staff: Thanks for the additional Info. We appreciate it.
- Nick at Pelican Parts
Check out some other sample projects
from the book: