nagging coolant leak solved

[Tom F&L GoR]

Do you have a healthy Viper but have to add coolant every once in a while? Do you get hints of the dreaded "cylinder wall shift" of Gen 1 engines, but it never seems to get worse? Is your Viper older, or higher miles? Then read on…

I've installed a coolant flush "T" on one heater hose line, since that's the highest part of my cooling system. To check the coolant level or add coolant, I unscrew the cap and fill from there. Except I found that filling at the heater hose would simply allow the coolant to drool out the radiator cap overflow tube and fill the overflow container. Turns out that the (correct) replacement radiator cap is a "drop center" style, meaning the vacuum vent vavle (the disc in the middle) simply hangs down. According to a cooling system engineer, when an engine runs, pulses from the coolant flow or expansion push it up and closed, and then it stays up until the coolant cools down and shrinks. But he added that these caps are on the radiator itself, not on a remote surge tank system like Vipers have. Other remote tank cooling systems use a "spring center" radiator cap, which has a weak spring holding the vacuum vent closed. I have since put one on, and I notice 1) the radiator hoses are "tight" after a hot shutdown, and 2) no more occasional "gurgling" due to no pressure on the system. Either I had a really bad cap, or the drop center style cap isn't the best choice. Comments anyone?

And… I found that the short rubber hose connecting my radiator neck ****** to the overflow container was not airtight. So when the engine warmed up, it would push coolant into the overflow container, but then when it cooled off, it would allow air to get sucked in. Then since the surge tank isn't quite the highest spot, the surge tank would refill with coolant and push the air somewhere else. The next time the engine warmed up it would push out a little more coolant, and **** in a little more air. After a few months, in my case, I'd find the engine would run hot, coolant would boil in the block, and puke coolant out of the overflow because of the steam. I've since replaced the rubber hose and added clamps (no clamps is stock) to make sure there's a good seal. Comments on this one?

Anyway, the engine has always run strong, and still does. With the other style cap, new hose, and clamps, it has a different (better) pattern of temperature gauge readings, so I've done something to improve things. I can sort of attribute it to age, but the radiator cap issue is technically interesting. Hope this little diary entry helps some of you…..

 

[Qualitywires.com]

good stuff to know. Thanks for the write up . I will have to check mine.

 

[garolittle]

I want to hear what Jon B. has to say about this one. By the way, I would suggest adding a large bottle of "Stop Leak" the next time you flush and fill the coolant system.

 

[kverges]

On my '93, I have had no similar problems, even on track. I check my coolant level between track sessions when everything is REALLY hot and use my bleeder fittings
http://www.viperclub.org/news/bleedersannouncement.html

which are refrigerant-grade schrader valves "T'd" into the upper rdiator and heater hoses. I can do this with a hot, pressurized system after shutdown to release any air or steam pockets. So far I have used no coolant in the past year.

My radiator cap acts like a spring center version, and I know it is original since I am an original owner of my car (I know, the rad cap should have been replaced by now, but if it ain't broke . . . .).

My new project (almost done) is the bottom breather (copying Roe's GEN II setup since he does not offer one for GEN I cars) to capture high-pressure air from under the fascia and direct it through the radiator. I need all the help I can get here it Texas, especially since my car is so early that even the later fan module won't fit.

 

[Sean Roe]

Hi Keith,

You can copy it if you want to, but I do make them for all model years.
http://www.roeracing.com/index.html?token=1715689423-865705709-1520281876&A=3&B=Cooling
Either way, it works and your car will run cooler.
See you later.

 

[JonB]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by garolittle:
I want to hear what Jon B. has to say about this one <HR></BLOCKQUOTE>

1) I thin TOM has always been an asset here. I read and heed his every word.

2) Keiths 1993 (and any 1992) is DIFFERENT. WAY DIFFERENT. (TYM)

3) I did EXACTLY what Tom did, with no fancy bleeders, because I live on a budget. A $3.95 Prestone Hose Bib looks tacky but works ALMOST as good as a clamped-in Shrader valve which I ALSO recommend from keith, by the way!

4) I knew about the "drop" neck of the cap, but not the language. I sleceted a Lev-R-Vent Stant cap of the proper rating, "drop", and diameter of rubber washer/seal.

5) Later Surge tanks are clamped w/ small spring-clamps, stopping the "vacuum loss" as Tom describes between facia bottle and surge tank.

6) Proper gasket and H2O pump maintenance includes regular coolant flush n fill, (60% H20)and for those gaskets already signalling impending doom, with aroma or seepage, you cannot hurt it worse by adding gasket-sealer-goo I suppose. I would. (see budget item above!)

7) The gurgling and taut, pressurised hoses when HOT are exactly what Tom says: Steam pressure. BURP TIME. Viper has Colic.

Bye for now........

 

[Tom F&L GoR]

Thanks, all.

Keith, if your car is that early, you don't have the fascia tank? If not, then the spring center cap would be the correct cap, according to the coolant engineer. So that makes sense.

JonB

I got my garden hose "T" for $0.99 at the auto parts store. And to find that later cars have added the hose clamps makes sense. Yes, the hoses are now tight, but no gurgling. While temp gauge was *usually* about straight up, now it's *always* pointing about straight up.

Sean, I copied your bottom breather opening a while ago, even used the cut out urethane fascia piece as the air dam, figuring I could make it so low it scrapes often. It will eventually wear to the lowest liveable level. Great idea, works terrific.

PS - take a look at the heater hose (the side without the control valve) as it goes behind the right side cylinder head. Mine rubbed against a plastic wiring harness plug and is nearly worn through.

 

[kverges]

Sean,

Now I feel bad! Did you always have the earlier car kit? I bought your Gen II kit and I could swear at the time that you did not have one for the RT/10 (this is an OLD project I am only now getting to). The RT/10 setup is significantly different for me, since there is no "built-in" airdam to work from as in the Gen II fascia, so I had to fabricate that along with the hole & so on.

I do have the fascia overflow tank, but my cap sure acts like a spring cap. Maybe I had better look at it more closely . . . .

Thanks for the pointers from everyone!

Keith

 

[Jack B]

Keith:

Roe does have a kit for the Gen I. I installed one about one month ago. I installed it to get rid of the front end lightness that the Gen I's experience above 120. At 125-130, the car no longer has that floating feeling.