Coolant crossover photos

[ewill3rd]

I can do it in the shop, I don't do side work though so if you want me to do it you'll have to bring it in.

Can you get PM's?

[BodybyFisher]

Originally Posted by ewill3rd

8.2,
Usually the crossover leaks never hit the ground. They are pretty small and usually evaporate from the engine heat before they leak down to the floor.
Sometimes if you look carefully you can see residue or a puddle on top of the transmission, over behind the engine.
If you are underneath you might see some coolant drips where the engine and trans bolt together, but as I said most of the time you won't see anything on the floor.
On an '03 Deville I think there was a bulletin for an updated design cover that is more resistant to thermal cycling. That is probably what they did to your car last time.
The reservoir has a tendency to fail after a cooling system repair.
I get burned all the time, when we fill them up the sensor float dies and the low coolant light stays on. It can be an expensive part and I hate having to make that second phone call to tell someone after they fixed whatever component in their cooling system, now they need a reservoir.

I understand why the reservoir fails, but does it fail immediately?, and did you say you got burned when it failed? Why does the low coolant sensor float die when you refill them?

I am doing this job now on my 96 Deville. I am having difficulty getting to the lower rear bolts near the firewall. Do I need to remove the electrical harness to get clearance?

The electrical harness goes to the O2 sensor, fan relays, ABS, and I think the oil pressure switch, does it go to the oil level sensor also? Are there any tips or precautions to getting this harness out? The harness appears to include fuse modules from the relay center also.

I was thinking that I would like to affix the gaskets in place can I use the GM Assembly Adhesive (comes in tubes, that may not be the name), to hold them in place?

I was thinking of using a locking flex head ratcheting wrench, what do you use to get at those bolts? Thanks for any help, Mike

[ewill3rd]

Mike,

You will have to "move" the harness out of your way.
There are a few connections you'll have to unhook and some grounds you will have to remove from the block.
The coolant temp sensor is in the back with a ground wire.
You just have to loosen everything enough to pull it out of the way, that is the real challenge of the job.
I use a ratcheting flex head wrench on the hard ones and some regular stuff on the ones that can be reached.
Don't glue the gaskets on, put them on dry. Just put the seals on and put the bolts through and balance the crossover so they stay in place (quite a challenge but doable).
Sealers and adhesives will just make them leak sooner.

As for the reservoirs...I am not sure why they fail, sometimes they fail right when we fill them up, sometimes after the test drive when we are finished.
No rhyme or reason but they seem to just stop "floating".
HTH

[BodybyFisher]

Thanks ewill, that is a BIG help, I appreciate your tips greatly. I will post my experience and photos next week. There is not much information in the FSM for some reason on the crossover. The SI info shows 18 ft lbs for the 8 bolts is that torque spec still good?

Are any of these bolts WET? I took a couple of the bolts out and they were wet with coolant and coolant poured out. I was surprised to see that. The bolts that were WET had a RED coating on the threads (thread lock?), must I replace that coating?

In conjunction with this job I am replacing the ISS speed sensor. Thank you, Mike

[ewill3rd]

Are you taking the trans out?
The ISS is a much bigger job than the crossover that is for sure.
You don't have to remove the trans for the ISS but I was just wondering.

As far as the bolts being "wet", they go through open holes in the head so when you remove them you open the water jacket, coolant will run out.
I'd have to look to see if they recommend sealer on the threads.
For something like that I might recommend cleaning the bolts and using a liquid teflon type sealer and torqing to that spec, should still be good.
I'd have to get out the paper manual to see some of that stuff, '96 didn't have much on the computerized version of the manual.
It is hard to torque most of them because of where they are, but you can use your torque wrench to get a feel for how tight they should be.

Good luck, let me know if you have more q's.

[BodybyFisher]

Thanks for the info on the bolts being wet, if you find out anything about the teflon sealer I would appreciate it..

Yes, I am dropping my carriage using 6 bolts and nuts to slowly drop the carriage. Logan recently used this techique. My main job was the ISS sensor, this crossover is the 'lead in' Here is my ISS thread and Logans link to his 'bolt method'. Thanks for you help, I may lean on you again at some point, Thanks

ISS Sensor Thread just beginning:
http://caddyinfo.ipbhost.com/index.php?showtopic=13481

Logan's bolt method, see the link in the first post:
http://caddyinfo.ipbhost.com/index.php?showtopic=13518

Thanks

[TheeSlowPoke]

Hello ewill,

I noticed two drops of antifreeze on the floor yesterday. Couldn't find where it is coming from, noticed a drop where the engine and tranny bolt up on the left rear of the engine just ahead of the flywheel. Figure it is from the crossover.

Do I "need" to fix it? So, what if I don't take it apart and replace the gaskets and just let it leak?

What's next, are the head gaskets going to need replacement soon, too? If so, would it hurt just to wait until then?

Reading through your thread you mention the reservoir - are you saying to replace it while the crossover repair is being done? Sounds like it, but I am not sure.

[Ranger]

No, leaving it alone will not cause a head gasket failure. If it is a very small leak, add 4 sealant tabs to the radiator hose and that may seal it up.

[TheeSlowPoke]

OK - Thanks Ranger!

I had the coolant replaced in my 2000 DTS last summer. This is the one with the leak. I doubt they put the tabs in. They did use Dex-Cool.

[ewill3rd]

Head gasket failures are often a result of cooling system abuse. As long as you keep the system filled a small leak won't hurt much. It will just leak and cost money to keep it filled and make a mess.

What I was talking about with the reservoir is that they often fail when the system is drained and refilled.
It is not a mandatory replacement, just often times it will need done after the car is fixed.

Seal tabs might help for a while, you should eventually get this fixed.

[TheeSlowPoke]

Pulled the bottom hose last Thursday and added three crushed tablets. Lost only about 1 pint of coolant in the process.

Earlier this year I had the car in to a local shop to have a leaking A/C line replaced and the A/C system charged. I had him replace the water pump (it had a small leak at the time) and change the coolant while he was at it. The dex-coolant that drained out when I pulled the hose last week was clear - I called and asked the guy if he added the additive as is recommended in the manual and he said he didn't. So, it has been running with straight Dex-coolant for the last 7 months.

So now, I will wait and see. Actually, I will crawl under and take a look tomorrow. Hopefully I won't see any indication of further leaks.

Thanks for your help!

[mtflight]

Sorry to revive this thread... if it takes 6 hrs for a novice, how long does it take for a pro? My "friendly" Cadillac dealer is $125/hr. 03 DHS smelling coolant, none on the floor... for about a month or longer... Couple' times I've seen a small puddle about the size of a quarter right by the metal brace between engine and trans. When up on a lift, I can't see anything, but if there was a leak I would suspect it's that same area.. between trans and engine, toward the driver side. Nothing can be seen from the top and I've used flashlights and mirrors.... these pictures tell me it is probably one of those small gaskets.... kinda bummed about that.

Is this why the original N* had the coolant sealer pellets put in, to avoid too many of these nuisance leaks? This morning, on the way into work I get the "Check Coolant Level" After reading this I am going to top off that coolant ASAP so as to not damage the float level sensor...

I'm wondering how long I would stall this from worsening, if I added said Barsleak powder as I added on the Eldorado religiously with each coolant evacuation/refill?

[Ranger]

If it is a small leak, there is a chance that the tabs may seal it. Don't go crazy with them or you may clog the heater core or radiator.

No that is not the reason for the tabs. This crossover leak seems to be more prevalent on the 2000+ engines for some reason.

[mtflight]

Originally Posted by Ranger

If it is a small leak, there is a chance that the tabs may seal it. Don't go crazy with them or you may clog the heater core or radiator.

No that is not the reason for the tabs. This crossover leak seems to be more prevalent on the 2000+ engines for some reason.

I just got back from topping it off, and was surprised I was only low about an inch from the full-cold mark (I probably added about 1/2 - 3/4 cup of Dex 50/50 pre-mix when cool).

By the way, I'm not sure I understand all the markings and indicators on the coolant reservoir tank. I see the "FULL COLD" line that apparently points to between the black part of the tank and the clear part. Then some marks on the side (horizontal lines) then a protruding tab on the front left corner. The clear tank is an improvement from the dark ones, but figuring out where it should be is ambiguous at best, or it's too simple for me to see it that way.

Did the 2003 (mid-year) come with the sealant tabs? I see no labels indicating so. This car had the water pump changed almost 2 years ago, at 40-some-K miles at the dealership.

[Ranger]

The coolant level is not that critical. The halfway mark (between black and translucent) is about right when cold.

They stopped using the tabs around '01 I think. I don't use them anymore.