anti-freeze coolant! I was driving with my kids the whole day yesterday with the ac on the whole time and upon parking the 97 disco, I heard a hissing sound and smell a little anti-freeze. The next day, we did the same again driving around with the ac on and after about 2 hours on the way to point C, the check engine light came on! I popped the hood open and didn't see anything wrong in particular, just the same hissing noise coming from the radiator and a smell of coolant. I top it off with synthetic oil just to make sure I don't toast the engine!
Engine light still on and I'll wait until the next day to see if it's on again and maybe, I should replace the radiator hose since it's pretty old!
Any ideas why this happened?

 

Well lets start with your mileage. Please also post that in your signature.

Where was the temperature gauge during all this?

1. You'll need to get the check engine code(s) to figure out where to start with the check engine light. If you drive it with the check engine light on you will run rich and your gas mileage will be crap until you have it cleared, so have it checked/cleared ASAP.

2. When the truck is cool you'll need to check the coolant level.

3. If you see a visible leak tell us the general location. If not have the coolant system pressure tested.

If your overheating adding engine oil will not help you prevent a fresh set of blown heads. Do not allow your truck to overheat or you will warp/blow the heads. Keep a close eye on your temp gauge.

Do those tasks and get back with us.

 

The hissing was probably the pressure relief cap on the resivoir. It was probbably running a little hot if the hissing was loud enough to hear it. If it happened with the a/c on, make sure both electric fans behind the grille are running with the a/c on.

I would go to autozone or similar and have them read the check engine code. I doubt it is related to the hissing sound, but you never know.

 

Thanks for the quick responses/advices folks! The truck wasn't over-heating, the gauge stayed the same and runs the same ( fingers crossed )!
The truck is nearly 140,000 miles!
I will give an update tomorrow as soon as I can
Thanks and have a great evening ( pacific time )

 

Before I start off, I would like to thank you guys for the knowledge you all are sharing! This forum rocks big time!
Anyway, I went to purchase a scanner and did a scanning and I would be grateful in anyone can define this codes for me.
upon hooking it up and starting the engine, this are the readings I got while scrolling down:

1 code
p0441
mil stat = on
monitrs
0 inc
misfire
7 ready
misfire
fuel
comp
catlyst
02 sensor
02 htr

Thanks and kind regards
Erwin aka roving patrol

 

I did a little research and found out that there could be 2 faulty things I need to correct the code ( 0441 )
1 Gas Cap
2 Purge valve

I again thank this forum

 

A few things to take into consideration, with the age and miles on your truck, where are you on the required periodic Maintenance? Have you performed the things listed as done at 60K mile interval? Do you do the upkeep or do you wait for a problem to pop up?

 

As the second owner of the truck, I tried to keep up with the maintenance and had a copy of the carfax vehicle history report which is pretty clean! I got her with 107,000 miles and so far, all I've replaced are the ignition and the fuel pump!
I order a few spare parts whenever I see a good deal even when I don't need them at the moment just in case! I follow in timely manner the fluid replacements ( oil, tranny oil, etc....) There are some failures that sometimes cannot be avoided by maintenance like the sunroof being de-railed and a rear door lock that requires a key to open at all times! But those are pretty much normal problem with wear and tear for an old truck IMO!
I'm the kind of person who always think ahead and not behind!
Thanks

 

So do you have new hoses, thermostat and antifreeze in it?