: 98 deville coolant smell?

03-08-14, 12:13 AM
Hi there, I'm new to the n* and just purchased a 98 deville with 240k on I today. The car was sitting for two years but was started every few weeks so nothing fell apart. Anyway the question I have is I checked all the fluids in it before I started it and topped off the coolant as it was pretty low from sitting. Car hadn't been on road for a long time. It runs absolutely mint nk warning lights and as smooth as can be. I have a feeling I may have slightly overfilled the coolant and I noticed as I drove it to the shop to get the oil changed I could smell the sweet smell of coolant inside the car. It is not leaking or anything and still has heat. The coolant temperature on display stayed between 94-105degrees celcius. I am getting the coolant flushed on monday but should I be worried about this issue? The car seems to be driving perfectly fine. It has a slight steam from the exhaust but I'm assuming thats the moisture In the exhaust burning off after for sitting.

Anything I should look for in the future? I'm a very lite throttle driver and dont drive it like a race car so abuse isn't an issue.

Also should I give the mechanic these sealant pellets I hear of? And how much do they cost

Thanks in advance! mike


03-08-14, 12:57 AM
Have it pressure tested. Or place cardboard under to catch any drips, dex cool will leave a chaulky white residue

03-08-14, 08:19 AM
Don't use the pellets. If you're smelling it there is a leak somewhere. I wouldnt get it flushed until you find it or may be wasting your money.

03-08-14, 09:16 AM
White exhaust vapor is perfectly normal at startup - every car does it - look at tailpipes at the stoplights, particularly in cold/cool-humid weather. Billows of steam that smells like coolant is NOT normal.

Short startups at 2 week intervals is not good - the best thing you could do is to check the tires for dry rot, adjust pressures to 32 psi all 'round, check the engine/body fluid levels, and head out on a 250 mile road trip. Use it as an excuse for a remote lunch. Make sure there is a fair amount of open highway running. Fill the tank with a local Top Tier gasoline - Google it.

Proper coolant level is halfway up in the surge tank, cold. Never check/adjust coolant level with the engine warm/hot. That surge tank serves several functions, one of which is to absorb the results of coolant expansion and contraction as the system heats/cools. Normal.

Read the several fan and cooling system stickys just above this thread. Study the entire Cadillac Technical Archive way up ^^^ in the top black bar. Don't baby it. Read the owner's manual twice. There's more to the car than meets the eye. Study and practice the sticky post "How to pull codes" and how to find the definitions of what is stored in the system. If your car is a model year 1998 it would have been built between ~07/97 and ~06/98 - the build date is on the sticker on the driver's door.

03-08-14, 10:00 AM
topped off the coolant as it was pretty low from sitting.
Wrong. The cooling system is sealed. It could sit for 20 years and the coolant level should never change.

I have a feeling I may have slightly overfilled the coolant and I noticed as I drove it to the shop to get the oil changed. I could smell the sweet smell of coolant inside the car.
The only way you would smell coolant from "overfilling" is if you filled it almost to the top. You can probably go as high as 3/4 or even a little more before it will expand enough to overflow.

If you could smell it inside the car, it may be a small leak in the heater core.

Also should I give the mechanic these sealant pellets I hear of?
:tisk: I'll second Rodnok, absolutely not.

03-08-14, 11:20 AM
Shoot I filled it to the top, better fix that. Also I put cardboard underneath it and there are zero leaks


Also is it normal for the temperature to sit between 95-105 degrees Celsius?


Also while I'm on the phone, can I use zerex g-05 coolant in the car? Or just dexcool. Cause I've had great luck with zerex in my 87 Benz and Lincoln and Volvo etc

03-08-14, 01:29 PM
Sorry for all the questions in advance I'm just really happy that I got this car! I want to maintain the thing tip top to make sure it's in great shape

03-08-14, 05:07 PM
Your thermostat doesn't even begin to open until 188 degrees F (87C) and is fully open at 206 F (97C). If you're idling or stuck in slow traffic with the HVAC OFF, cooling fans do not go to SLOW until 224F - 107C, and the temp will then drop to 213F - 100C, fans shut OFF and the cycle begins anew.

Read the sticky posts just above - cooling system, fans, gauges. Info you need. If you had studied the recommended reading in Post #4 you would understand cooling fan/system operation.

You can use any coolant you please - as long as you use a protracted fresh water flush to remove any other coolant traces........... and religiously exchange the coolant every 3 years.

03-08-14, 05:14 PM
They have prestone dexcool coolant at canadian tire for a good price. It says its designed for gm cars is this the coolant I should be looking for? And how many litres should I get? Thanks again

03-08-14, 05:20 PM
DEX-COOL is just fine. IF you use a shop vac to purge all coolant from the entire system you will need just shy of 3 gallons of 50/50 coolant - 14+ quarts. (It became the universal GM coolant in 1996)

To make your own 50/50 coolant, use raw (unmixed) DEX-COOL and gallon jug distilled water from the grocery store. Find a 2 quart clean pitcher. Pour 2 quarts of distilled water into the pitcher. Refill the water jug with raw coolant, pour the water into the coolant jug. BINGO - 2 gallons of mixed coolant and a clean pitcher.

Study all you can find in here concerning the cooling system. You will have hoops to jump through as far as complete refill, bleeding, and air/gas purging to prevent air pockets leading to water pump cavitation and overheating.

If you have a reasonable budget for vehicle maintenance, may I recommend a GM dealer "Spring Fluids Special" ? Not cheap - but they will exchange the coolant, transmission fluid, P/S fluid and brake fluid - all with the latest GM-recommended products. If you're not a good Northstar gearhead with a shop and decent tools/equipment, this may well be the best initial maintenance route for this severely neglected car.

03-08-14, 05:26 PM
I want to supply my mechanic with the dexcool so he doesn't charge me for going to get it etc lpl. They will most likely flush it out with some vacuum thing.


I'll get 12 litres of dexcool 50/50 premixed coolant tomorrow, that should be enough?
Also should I add distilled water to the premixed or just put in straight premixed

03-08-14, 05:30 PM
Premixed is just that, pre mixed. It's ready to use out of the bottle.

You could buy half as much by buying full strength coolant and mixing it with distilled water (50/50).

03-08-14, 05:32 PM
Premixed ANYTHING is a hideous theft operation. Mix your own.

"Premixed" is just that - 50/50 water/coolant. Mix your own for ~1/2 the price.

I hate to ask, but are you reading ANY of our posts ????

03-08-14, 07:34 PM
I'm trying to read some of the posts but my phone keeps resetting and won't show half the stuff that comes up lol. I really do appreciate the help though!

03-08-14, 07:41 PM
Reset the app or go to the full site.