Coolant leak 4.0

[cfscfs151]

Hi, I’m sure this has been addressed but I searched and couldn’t find specifically what I am looking for. I have a 1997 Aurora that was parked about 4 years ago. I have pulled it out of storage and have it running. I received the dreaded “low coolant” message on the car and it didn’t have this before it was parked. I opened the reservoir to top it off and when I dumped a gallon of Dex cool in it could hear it running out underneath the car. It is coming out in a stream on the drivers side rear of the engine. I have looked from the top (hard to see) and from the bottom to try and figure out where it’s coming from. I plan on replacing most of the hoses even though some of them appear to be ok. Any help in this would be greatly appreciated to get the car back on the road. I traced the hoses that come from the coolant reservoir and it apprears they go over the engine and behind it like between the firewall. I just can’t seem to figure out where it’s coming from. Tried looking at a gm parts diagram but that didn’t exactly point me in the right direction. Thanks for any input

[RCA1186]

It is probably the heater hoses that go into the firewall. They're tough to get to, easy to replace. I had to pull the coil packs, cruise control module, main wiring harness connector etc, to be able to reach it. Could be the coolant crossover (the part the water pump is mounted to that goes to the other side of the engine) the gaskets leak on these but usually not in a stream like that.

Part of the heater hose is a metal pipe that could have rusted through while it was sitting as well.

[RCA1186]

Mar 14, 2018 17:12:16 GMT -6 tigger said:

'97-'99 Heater Inlet Pipe. #3 below, GM 25642181.

Everything within the [10] is located in the area you specified 6/9 are the hoses

[cfscfs151]

Thanks for the diagram. I’m probably going to have to raise the vehicle and get underneath while someone dumps some water into the coolant reservoir so i can see where it’s leaking from. If in fact it is one of the pipes that’s rusted are these available or am I out of luck?

[RCA1186]

It may be discontinued, not certain with that one. You could probably just run a long length of heater hose in place of it though. Autoparts stores sell it by the foot. Might take some zipties to keep it in place.

[cfscfs151]

So, I had an occasion to look farther at the leak. When I originally dumped the coolant in it appeared to be coming from the left rear of the engine . After taking another two gallons of water and dumping in to search more closely for the leak I hear it running out up front underneath where the water pump is located. It must have been traveling along the cradle of the engine to the rear but I could definitely tell it was running from there. I tried to push my hand under the water pump casting and could feel water coming out but could not see just where. The only thing I could maybe figure is years ago regular cars used to have a weep hole on the bottom of the water pump. And coolant would come out there when the water pump was bad. I’m just wondering the same issue here ? I have also looked at the hoses and while some of them have some age I couldn’t find one the was split or leaking? I apologize for the updated post but things changed when I realized it wasn’t leaking where I originally had stated . Any help or advice would be appreciated

[ljhermsen]

Apr 28, 2020 14:30:31 GMT -6 RCA1186 said:

It is probably the heater hoses that go into the firewall. They're tough to get to, easy to replace. I had to pull the coil packs, cruise control module, main wiring harness connector etc, to be able to reach it. Could be the coolant crossover (the part the water pump is mounted to that goes to the other side of the engine) the gaskets leak on these but usually not in a stream like that.

Part of the heater hose is a metal pipe that could have rusted through while it was sitting as well.

OK everyone, my son's 2003 4.0 is leaking coolant from the crossover gaskets we suspect. I currently have EVERYTHING apart and 6 of the 8 crossover bolts out, EXCEPT the back 2 bottom bolts. How in the heck does a person even get at those 2 bolts? I'm about a flip of the coin away from just putting everything back together, using some K-Seal, and crossing my fingers.

Suggestions needed ASAP.

[Paulaurora]

Try those videos www.youtube.com/watch?v=BYcG3N0UTRU www.youtube.com/watch?v=okHzWE212lo www.youtube.com/watch?v=R36k7gz6kYc its cadi but i am sure its 99% same .

[ljhermsen]

OK, I did get those back 2 bolts out and the crossover gaskets switched out and everything back together. What a PITA (Pain-In-The-Aurora). Paul ~ Thank You very much for the link. It wasn't the exact same, but it definitely did help with this repair. BTW, if anyone wants to know what the best thing since sliced bread is, it's GEARWRENCH's. Definitely a handy tool for a project like this.

Love this Forum.

Now I'll know how to repair the crossover pipe leak on my Final 500 Aurora someday. Hopefully that will be awhile though as I just turned 22,000 miles over on it last week.

[Paulaurora]

Nice that it helped you:) You should of recorded it and put on youtube hehe:)

[ljhermsen]

Thought about it, but way too many swear words involved from start to finish.

[Paulaurora]

Mar 27, 2022 8:53:06 GMT -6 ljhermsen said:

Thought about it, but way too many swear words involved from start to finish.

ROFL