Replacing the coolant crossover pipe

[Tobey]

My 2000 has been losing coolant extremely slowly for the last 4 years. The low coolant light would come on once in a blue moon, I'd top it off and all was good. Oddly, some months were worse than others. Some months it would be so bad that air would get into the system and I could hear bubbles gurgling around.

I could smell it, but never could find out where it was coming from. Nothing in the oil, and no coolant from the exhaust. I didn't worry about it too much-- I didn't want to because part of me was sure it was the head gasket. Last week I walked into the garage and found a small puddle of coolant on the floor on the driver's side. A small mirror revealed it was those darn crossover gaskets failing. Couldn't ignore this any longer!

Glad to say, thanks to this thread, everything went off without a hitch. Not a fun job, but actually not terrible. It looks harder than it is. I opted to remove the rear manifold and do it right. Prying on it felt too risky to me. The whole thing is about an 8 hour job if you really get at it. Also glad I had to pull the throttle body off. Turns out the paper gasket was spitting coolant into the air intake! Cooling system is now tight as a drum and no issues to report.

I should mention Stevie's parts list is pretty spot on, EXCEPT it seems the rubber heater plate gasket was revised after 1999, so his gasket is wrong for later years.

Here's parts the list revised:

• 35722 (QTY 3 needed) manifold x-over gasket
• 70788 EGR valve gasket (graphite)
• 61304 Throttle body gasket (paper)
• 61305 Throttle body heater plate gasket (molded rubber) FOR 1999
• 61306 Throttle body heater plate gasket (molded rubber) FOR 2000-UP
• MS96346 Exhaust manifold kit (left, right and flange donut)
• 61310 Rear manifold to cat gasket

That's everything you need to do the job right (or mostly right). Plug those part numbers into rockauto and you're good to go!

Here are some (mostly exhaust related) things I learned along the way that weren't really mentioned or talked about in great detail here. I figured I'd share with the class:

• Don't pry on the exhaust manifold. Mine didn't move nearly enough to be helpful without putting a large amount of force on it. It's just a bad idea. You're putting a ton of stress on a possibly brittle manifold, its bolts and your aluminum head. If you break any one of those, well now you have to drop or pull the engine. The exhaust manifold really isn't that difficult to remove and replace. I spent more time trying to figure out how to avoid unbolting it than I did actually unbolting it.
  
  
• You'll need to loosen the steel secondary air injection pipe so you can move it out of the way when necessary. It won't move much, but just enough. It's bolted to the front of the tranny and held to the vacuum operated valve with a rubber coupler (no clamp). You might also have to unbolt the vacuum valve too (3 10mm bolts). It's got a stiff metal flex tube attached to the bottom, don't disturb this connection. It'll move around plenty with the tube attached.
  
  
• Ramps are more helpful than jack stands to really help to reduce the risk of a car crushing you.
  
  
• Drop the exhaust system and slide it out of the way to give yourself more room. I can't imagine working on the manifold with the cat poking me in the back of the head. It's just a few rubber hangers, use WD40 to get them to slide off their studs. Don't forget to unplug the downstream O2 sensor!
  
  
• Remove the entire dogbone strut assembly from the front and use a ratchet strap there to pull the engine forward. This helps give better access to the manifold bolts.
  
  
• All of the exhaust and coolant crossover bolts are 1/2”. 13mm is too big and will round the heads off. The bolts are all torqued to 18 ft lbs and should come out easy. You need a ball style wobble and some extensions for the manifold. Soak the cat to manifold bolts and manifold flange bolts in penetrating oil before busting them. An impact gun is very helpful.
  
  
• THOUGHROUGLY clean around the tranny fill tube before removing it! You don't want tiny rocks falling down in there and there will be rocks around it.
  
  
• When unbolting the manifold from the head, break all of the bolts loose first, then focus on removing them without dropping them. Remove the bottom bolts first since they're harder to get to. You'll be straddling sub frame structure to get to top and bottom bolts. You'll be removing and installing them using your socket and extensions. Press a small strip of duck tape into your socket and fold the ends over the walls. This will help grip onto the bolts. This is very important if you don't want to lose those bolts between the engine and tranny, I lost exactly zero bolts using this trick. By the way, an empty coolant bottle makes a great pillow for your head when working under there!
  
  
• None of the exhaust gaskets are reusable. Don't even think about it. The graphite flange donut, the manifold gasket and manifold to cat gasket are a one-time-only crush gasket and may leak if reused.
  
  
• Don't remove any EGR tubes from the coolant crossover. They have a one-time-only crush seal built into the tube and may leak after. The front one can be removed from the intake manifold, it uses an orange o-ring for a seal and a new one is supplied in the fel-pro exhaust manifold gasket kit. The rear one can actually be left alone entirely, it's flexible enough that you replace the crossover gaskets and clean sealing surfaces with it in place. Don't yank on it so much that the factory bends straighten out. When you get the crossover out, use a bungee hooked to the hood to hold it out of your way while cleaning sealing surfaces.
  
  
• On the exhaust flange, remove the old donut and clean up the flange collar while the manifold is still unbolted from the head. The collar with the donut pressed into it will slide off the front manifold. Take it to your bench and remove the donut and clean the collar up with a wire wheel. Replace the collar and put the new donut on at this point. Don't bolt the flange together until after you've bolted the rear manifold to the head, you don't know where the connection wants to rest yet.
  
  
• The hardest part about the manifold is getting the new exhaust manifold gasket back in there without getting it covered in sand and oil or dropping it into no-mans land. Must have spent 45 minutes fiddling trying to get it to slide down into place. Turns out I just needed to give the manifold a little extra tug to get it away from the head, this meant pulling it up out of the front manifold (another reason why we don't bolt that connection together yet).
  
  
• With the manifold away from the head, thread two bolts into the manifold gasket to keep the gasket mostly in place. Hold the gasket to the manifold with one hand and thread the top center bolt into the gasket a little ways with your other. Now do the top right bolt. You can hold the manifold and gasket with your left hand and get to the top right bolt with your right hand by reaching around from wheel well (at least I could). If you thread the bolts in far enough (1/4”) they sort of act as alignment pins when putting the manifold into place against the head. You may have to go up top and carefully mate it back up with the front manifold, don't be too rough or your bolts might fall out.
  
  
• When fastening the manifold to the head, start with the top center bolt, then the top right bolt, then the top left bolt. Use your socket, extensions and the tape trick to carefully thread them in by hand. This is the last place you want to jack threads up. To ensure you don't cross thread, don't use your ratchet. If the manifold is lined up correctly and your bolts are clean, you should feel little to no resistance when threading the bolts in by hand. If it's catching, back the bolt out a bit and readjust the manifold until it stops catching. Don't snug the top bolts up too tight yet, you need the manifold to move around to align the bottom bolts up. On the bottom bolts, same thing, use your extensions, wobble and the tape trick to install these. Again, don't use a ratchet. Start with the center, then the right, then the left. You may have to fiddle with the manifold a little bit to get these to line up. Now snug all of the bolts up by hand (using your socket and extensions) so the manifold has no movement. Take your torque wrench and torque them to 18 ft pounds. Start with the center bolts and move outward. YOU DID IT
  
  
• Now slide to the front of the car and bolt the flange together. Snug the right side up, then the left. Keep going back and forth so it doesn't bind. Torque to 18 ft lbs.

Take a beer break and put the rest of it back together later. You do remember where all those bolts go, don't you?