Coolant Crossover Gaskets?

[RCA1186]

Ok, so replaced my radiator, and got that leak taken care of (I did the upper and lower hoses while I was at it), thought my coolant problems were over, but alas, they are not. Last week or so I've noticed a stain on the pavement (in addition to the normal oil drip haha). I stuck some paper underneath to be sure of what it was, it turns out to be coolant.

As I just did the radiator, I assumed something probably wasn't tight. I had the car up on jack stands and ran it up until operating temps, revved it up to get it at higher pressure even, but noticed no dripping coolant. I inspected underneath and noticed trace amounts of coolant, but no definitive location of the leak. I let it cool down all the way and waited but still noticed no drips on the ground so wasn't able to find the source. It seems to only happen after driving and then sitting for a long time (such as overnight). When the car is running I don't see any leaks. The spot ends up being maybe four inches in diameter on the pavement its located on the driver's side (back of the engine) towards the front of the car. So by the waterpump, thermostat, lower hose connection. I don't think its losing a lot as the coolant level doesn't really seem to change. I have no problems with the temp, the gauge always stays right where it always has a hash below 200.

Also for the record, I did add the GM cooling system seal tabs to the lower hose (3 of the larger pellets) when I did the radiator. Some of the links below suggest those for stopping the leak that they had (I added them but had to add more coolant later because I lost some when I got the upper hose the day after I did the radiator) Perhaps try adding more?

My guess is the coolant crossover gaskets, but does anyone have any other ideas? Anyone have the procedure for changing the gaskets if that IS what the problem is? I have the FSM but would like to hear first hand experience. Also, I'm assuming I should be able to let it be at least until its warm, I don't think whatever it is is in desperate need of changing.


Found some similar leaks but I'm not sure:

aurorah.proboards.com/thread/14500

aurorah.proboards.com/thread/20208

aurorah.proboards.com/thread/28588

aurorah.proboards.com/thread/16668


Wondering if Randy still has the pictures for this link:

aurorah.proboards.com/thread/14833

[ohiobuckeye]

As long as car runs fine temp wise I would not do anything for a period of time/miles. The seal tabs will take some time to work. A month from now you'll know.

[sall]

May be your waterpump gasket. Any fluid around pump weep hole? Could be crossover gaskets though at least the forward most one.

[RCA1186]

Feb 17, 2015 12:31:50 GMT -6 sall said:

May be your waterpump gasket. Any fluid around pump weep hole? Could be crossover gaskets though at least the forward most one.

I did see a drip of coolant on the water pump housing but I noticed them elsewhere too...could be either the crossover or waterpump from where it was. Where exactly is the weep hole on the pump housing, is it on the bottom? I didn't notice one when I was under the car Saturday.

[sall]

TBH I am not even sure whether or not the Classic housing has a weep hole or not. I have not had to change one on either Classic yet . Usually the pump is integrated in the housing and have weep holes but of course this is a N* and it's a bit different.

[RCA1186]

That's what I was thinking myself. I haven't had to change one either and hopefully still won't have to. For now I'm going to see if the seal tabs do the trick like ohiobuckeye said, not in a hurry to do anything in this weather haha. Checked the coolant again today (first time I checked in about a week I think) and it looks to have dropped maybe a MM or two...so I'm not THAT worried.

[96nhaurora]

This sounds identical to a problem a had last summer. I was scratching my head for a couple of days until I was able to borrow a friends pressure tester, then came the "aha" moment. Dry everything off and then pressurize the system. Look for seepage/leaking, particularly around the pump housing/thermostat. For me the o-ring on the housing plate was slowly seeping coolant and eventually would cause a damp spot on the garage floor. Hope this is helpful.
C.

[Randy T.]

If they have not been changed in 5 years, all coolant crossover gaskets are bad, they are a poor design that break and split over time, Auroras/Cadillacs/Fords all have the same type of gasket and the same type of problem. I don't know what pics I posted in that thread, imageshack sucks now. They are not too hard to change, though, recommend ratchet wrenches if you don't have any yet, I also tap out the bolt holes before I reinstall, they come out a little tight sometimes. I think there may be pics buried in this thread somewhere, but not sure. 4.6 swap.

When you buy the gaskets they are labeled as "water pump gaskets" at parts stores, sometimes they have trouble finding them otherwise.

[RCA1186]

I saw the gaskets on Rockauto "waterpump gaskets" not too bad price wise at least. Still leaving a spot on the pavement, but not super severe. Maybe if I get a warmer day (currently 3 degress with -6 windchill haha) I'll go under and inspect it again.

[Randy T.]

I would also change your 2 heater core hoses and inspect all the metal pipes and hoses and flush the heater core. I have lost a few heater core hoses, one of the first repairs I remember doing on Aurora. Second time was on the way to Lances, when you don't have the right tools those hoses are a killer. If you want to drop a few bucks get some of those cable type hose clamp pliers, they are a life saver for Auroras. I bought mine a couple years ago, it's a Craftsman and still doing good.

Cable operated hose clamp pliers.

[RCA1186]

Feb 19, 2015 6:53:55 GMT -6 Randy T. said:

If you want to drop a few bucks get some of those cable type hose clamp pliers, they are a life saver for Auroras. I bought mine a couple years ago, it's a Craftsman and still doing good.

Cable operated hose clamp pliers.

Oh man, those things are nifty haha. Are the metal pipes dealer only?

[Randy T.]

That is a known unknown.

[RCA1186]

So, I went out today to check the coolant level, looks like maybe a quarter inch low, maybe just under half inch actually. I see coolant pooled in a divot on the water pump housing. Looks like maybe it came from where the water pump housing connects to the crossover. Is there a gasket between there ? I'd assume so. Or would this be from the o-ring/seal behind the pump itself?

That being said, if I were to replace these, is it worth it to re use the pump or should I just replace that too while I'm at it?

[RCA1186]

UGH, this is getting annoying haha, now the last two times I have driven...no coolant stain at all......maybe the seal tabs are working.

[sall]

Could be temp related too. Quite a while ago I had a trans line that leaked on my '96 but only when it was really cold. Warmer weather or operating temp no leak.

[RCA1186]

Hmm, temp's been pretty consistent last week or so except a couple days around the twenties (but mostly in the single digits to low teens)

[rorafan]

Here's hoping the tabs did the trick! They got rid of a nuisance leak I had in the same area. Never really ended up doing anything further with it since it went away.

And oh man, those pliers Randy mentioned are awesome. Saved myself some serious aggravation with those things a few times now.

[RCA1186]

The leak returns It does seem to be a little less than it was but it is still there. Sall may be right it may be dependent on temperature.

[mcgyverit]

I ran mine for about 2 years with the annoying leak from the crossover tube gaskets. it was getting to the point of having to fill the reservoir once a week as I waited for warmer weather to work on it last spring. the FSM is pretty straight forward, but there is a lot of parts to remove just to get down to the problem area. ratcheting wrenches are a must but the bolts next to the firewall and down at the bottom were a quarter turn or less at a time and the most time consuming. aligning the gaskets and the cooling manifold and bolts all at the same time was not easy. I used some of the sticky gasket spray on stuff to hold the gaskets in place so they wouldn't fall off during installation. it took 2-3 days to complete the job for me including draining the system. there is a large fitting right up at the top/back of the motor next to the firewall close to the brake m/c that I needed to cut an adjustable wrench down so that I could take it off as none of the standard length wrenches would fit. used a HF wrench and still keep it in my misc. tool drawer.

fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-xaf1/v/t1.0-9/10156072_685460374830761_992735825_n.jpg?oh=306551ecc6f95198d89beb612cd16755&oe=55AEE7F3&__gda__=1438392864_4a88d26fd2db384858fb2dd273447102

this is a shot of working on the transmission linkage selector, have to make room to get to the bolts behind it.
fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xfa1/v/t1.0-9/10157210_685460388164093_1211820814_n.jpg?oh=fa56dad32b9189b34d32670b2836681c&oe=55AD845B&__gda__=1438259540_3ad4e2a5070b3aaa396b9bc5f55e0328


this is after removing all the throttle body and acc in that area
scontent-ord.xx.fbcdn.net/hphotos-xfa1/v/t1.0-9/1392102_685460384830760_1061521402_n.jpg?oh=b44f672927a3fe92b7e5ec394ad29ba9&oe=55BC7E14

scontent-ord.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/10151778_687930374583761_745967761088717278_n.jpg?oh=fcfda5335b7b6241a59db7f279744e9d&oe=55BA02F6

this is the back side of the crossover tube
fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-xfa1/v/t1.0-9/1609701_687930377917094_7292007311342078620_n.jpg?oh=266f07b5b499fed2fa477ee931a7b893&oe=5576D026&__gda__=1438022518_7d0150819a501348ab44ca070d6f708f

these are the bolts I refer to as difficult, if you look closely you can see the silver wrench that is horizontal down in that hole.
fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xfa1/v/t1.0-9/10153292_687930401250425_1373570826761613181_n.jpg?oh=2939fc5039c4c6c5d7f02c7c6d7b5bea&oe=55BD6FA8&__gda__=1433680542_0d4dd0d081cbb100383972965435f9f9


this is the 10" adj wrench I cut down to get to the fitting on the back side of the crossover tube
scontent-ord.xx.fbcdn.net/hphotos-xfp1/v/t1.0-9/10247496_687930441250421_5115047240072631345_n.jpg?oh=7cbc35bd74a4d269943284e40d085fa9&oe=55AD14F3

Hope this helps

[Randy T.]

I think I forgot to mention you should tap out the bolt holes in the block for the crossover, they get a little rough.

[RCA1186]

Just a little update on this. No leaks to be found since I last checked in. Seems the seal tabs may have done the trick..or metal expanded when the weather warmed and it's going to return when it is winter haha.

[premiumV]

Is the coolant crossover and water pump housing under the throttle body the same things? One of my gaskets is leaking so much that I can't drive the car. You and mcgiverit mentioned the FSM. I looked everywhere in my FSM and I can't find the procedure. I can just keep removing parts but it would be better to follow the FSM.

Thanks!

Feb 17, 2015 7:22:31 GMT -6 RCA1186 said:

Ok, so replaced my radiator, and got that leak taken care of (I did the upper and lower hoses while I was at it), thought my coolant problems were over, but alas, they are not. Last week or so I've noticed a stain on the pavement (in addition to the normal oil drip haha). I stuck some paper underneath to be sure of what it was, it turns out to be coolant.

As I just did the radiator, I assumed something probably wasn't tight. I had the car up on jack stands and ran it up until operating temps, revved it up to get it at higher pressure even, but noticed no dripping coolant. I inspected underneath and noticed trace amounts of coolant, but no definitive location of the leak. I let it cool down all the way and waited but still noticed no drips on the ground so wasn't able to find the source. It seems to only happen after driving and then sitting for a long time (such as overnight). When the car is running I don't see any leaks. The spot ends up being maybe four inches in diameter on the pavement its located on the driver's side (back of the engine) towards the front of the car. So by the waterpump, thermostat, lower hose connection. I don't think its losing a lot as the coolant level doesn't really seem to change. I have no problems with the temp, the gauge always stays right where it always has a hash below 200.

Also for the record, I did add the GM cooling system seal tabs to the lower hose (3 of the larger pellets) when I did the radiator. Some of the links below suggest those for stopping the leak that they had (I added them but had to add more coolant later because I lost some when I got the upper hose the day after I did the radiator) Perhaps try adding more?

My guess is the coolant crossover gaskets, but does anyone have any other ideas? Anyone have the procedure for changing the gaskets if that IS what the problem is? I have the FSM but would like to hear first hand experience. Also, I'm assuming I should be able to let it be at least until its warm, I don't think whatever it is is in desperate need of changing.


Found some similar leaks but I'm not sure:

aurorah.proboards.com/thread/14500

aurorah.proboards.com/thread/20208

aurorah.proboards.com/thread/28588

aurorah.proboards.com/thread/16668


Wondering if Randy still has the pictures for this link:

aurorah.proboards.com/thread/14833

[RCA1186]

Oct 5, 2020 11:46:06 GMT -6 premiumV said:

Is the coolant crossover and water pump housing under the throttle body the same things? One of my gaskets is leaking so much that I can't drive the car. You and mcgiverit mentioned the FSM. I looked everywhere in my FSM and I can't find the procedure. I can just keep removing parts but it would be better to follow the FSM.

Thanks!

The crossover is the cast piece that extends from the waterpump and one bank of the engine over to the other bank of the engine near the firewall.


I am not sure the FSM is too helpful on this subject.

See if this video helps. www.youtube.com/watch?v=S1P66PM3Kus

The crossover is unbolted in that video, it is the long cast piece on the right. The waterpump mounts to it.


There are four small gaskets on the crossover housing


www.rockauto.com/en/catalog/oldsmobile,1998,aurora,4.0l+v8,1305357,cooling+system,water+pump+gasket,2148

called upper and lower in that link, they are sort of triangular.



Then there is a gasket on the actual hosing where the water pump mounts, and an o-ring that goes on the pump itself. This kit contains all of the needed gaskets plus a few others

www.rockauto.com/en/moreinfo.php?pk=2650056&cc=1305357&jsn=874

[premiumV]

Thank you very much for all of the helpful links. Did you end up having to do this job? The FSM calls it a water pump housing which is why I wasn't sure. I also found 2 more 3 part videos of this job on Cadillac's from the YouTube side bar. I was hoping my leak wasn't the water pump, now I'm wishing it was.

[RCA1186]

I have not had to do this job...yet. It is inevitable though from what I've seen and heard. My leak from this thread turned out to be a small piece of heater hose.


It essentially is the housing for the waterpump, it just happens to be the crossover as well. It doesn't look horribly difficult, just very time consuming

[premiumV]

I started the job yesterday and just have to remove the park/neutral switch top rear on the transmission, then I can start on the bolts holding the crossover on. The bottom 2 nearest the firewall look very difficult.

Something odd I need to deal with after this job. The leak happened in late June and I decided to let the weather cool off before investigating the problem. I haven't started the car since then and after I drained the radiator I thought it would be a good idea to start it briefly to make sure it ran OK. Well, there was nothing going on except cranking. It's good that I know this because I would be tearing my hair out focusing on this job for the reason of it not starting.

[jl205]

I have been smelling coolant near my 01 Aurora. And low coolant comes on everytime I start it. Last summer it overheated on me and since then I haven't had no more problems overheating. But I still smell coolant. Can you tell me if my water pump may be going out?