New '98 Deville Owner with coolant questions

olsonscottm · #1 (**permalink**) 01-11-09, 11:51 PM

Hello All,
New to the group, and new to Cadillac ownership.
I just picked up a 1998 Deville with 128K miles on it. Runs and drives great, with the exception of steam coming from under the hood. Not a lot, but a little. I bought the car, drove it 50 miles home, and could smell antifreeze.

I changed the oil and filter, reset the oil life indicator and fired her up. I got the "Check Coolant Level" message in the DIC. I added about 1/2 to 3/4 of a gallon of Dex-cool and went for a drive. When stopped, I could see a small amount of steam coming from under the hood on the left side. It was cold, about 5 deg. F. There isn't any puddling under the car, so I'm not sure where the coolant went.

I've read quite a bit about the car the last couple of days (thanks to all who participate in this forum, it's been very educational!) and hope it isn't the proverbial head gasket. Temps stay right between 210-220. I haven't seen anything hotter than 219.

My questions are: 1- Will a pressure check tell me if it's a head gasket? If not, will it show me where the leak is coming from? How do I check the water pump? How would I change the radiator? Pull the front bumper and all that stuff under the front of the hood?

Also, when I changed the air filter, I forgot to plug the air sensor back into the box, fired up the car and went for a 10 mile drive and the "Service Engine Soon" light came on. Once I plugged in the airbox sensor, I thought it would go away, but the light is still on.

Well, I've talked too much, but would like to thank all who participate for the benefit of others that you haven't met, it is appreciated.

Thanks, I'm looking forward to many, many miles in my new-to-me Cadillac (my first).

Scott
Palmer, AK

**Ranger** · #2 (**permalink**) 01-12-09, 12:20 AM

Destroyer will guarantee you that it is a head gasket, but he is a malcontent so ignore him. Head gaskets rarely if ever leak externally. If it is on the left side it most likely is a water pump, but could also be a hose or radiator side tank. Watch more closely to pinpoint where it is coming from. Use an inspection mirror and a flashlight to check the pump shaft seal behind the pump pulley. First find out where it is leaking from, then we'll help you fix it.

A cooling system pressure test will usually not diagnose a head gasket leak, but will locate a cooling system leak as the leak will eventually drip and not evaporate.

You can enter the diagnostic mode to clear the DTC stat set the SES light or wait for 3 ignition cycles after you plugged the sensor in. 3 cycles with no fault detected will send the DTC to history and turn off the light.

olsonscottm · #3 (**permalink**) 01-12-09, 12:26 AM

Ranger,

Thanks for the info. I just read another post that said to feel the inside of the tailpipe to see if it's slimey or not. So, I went and checked my tailpipes, and no slimey, just the usual black soot.

Now, how do I enter the diagnostic mode to clear the DTC Stat Set? (if it's already been covered, can you point me to the post?)

**Ranger** · #4 (**permalink**) 01-12-09, 12:42 AM

Go to the Tech Tips section and see the sticky at the top.

You DO NOT have a head gasket problem. Like I said, they almost never leak externally. If you where loosing coolant with no external leak, then it would be suspect.

dirt_cheap_fleetwood · #5 (**permalink**) 01-12-09, 03:53 AM

If it is not a headgasket issue and you do not see any puddling under the car and it is steaming than the leak is most likely near the top of the engine. The coolant is probably dripping onto the hot engine and evaporating/boiling off. Check the coolant return hose at the top of the engine for signs of wear/cracks/dry rot and replace as necessary.

olsonscottm · #6 (**permalink**) 01-12-09, 04:55 AM

I'm gonna have it inspected in the next day or two, but we found an auto shop invoice in the back seat, dated 11 days before we bought the car that states "over 1200 hydro carbons in cooling system witch show blown head gaskets and or cracked heads!! recomend engine replacement. note water pump housing is leaking also."

We'll see what a second opinion gets us.

**Ranger** · #7 (**permalink**) 01-12-09, 12:34 PM

Well that's not good. Save that invoice. That is good evidence that they knew of the condition and did not tell you should you decide to try for a refund. I still find it hard to believe that a head gasket is leaking externally unless you have 2 seperate conditions as the invoice seems to suggest.

olsonscottm · #8 (**permalink**) 01-12-09, 02:28 PM

I took it to a shop today, and the guy that can do the testing is off on mondays, so I have to wait until tuesday.

I'll let them check it out and see what they say.

The external leak may in fact be the water pump. If it is, I think I can tackle that repair myself. I'm no pro, but do know my way around an engine.

If the head gasket is in fact leaking, I'm presented with a quandary: do I suck it up and replace the engine, or try and fight to get my money back. I paid $2600.00 for the car (first clue should have been the low price, I guess) so by the time I add an engine in for who knows how much, is it worth it?

I found a place that will sell me a reman. 4.6L for $3250, plus $600 for shipping. I don't know if I can swap this engine or not. I only have a two-car garage, and don't know if I have room to drop the engine and pull it out.

Anybody know how much time it takes to swap one of these? Am I better off with a new engine for $4K, or getting a used one?

Thanks all, and especially Ranger.

dirt_cheap_fleetwood · #9 (**permalink**) 01-12-09, 02:43 PM

If you can have the head gaskets repaired do that over an engine swap. HG job usually costs between $3500 and $4000 and it will cause far less problems than an engine swap may cause. These cars are very technologically advanced pieces of machinery and they do not like when things change. Like Ranger said, use the invoice as evidence and try to get a refund for the car. I am sure there are laws in your area designed to protect consumers from this kind of thing so use them to your advantage.

misfit6794 · #10 (**permalink**) 01-12-09, 02:48 PM

What was the date on the invoice? If it was from awhile ago, they may have had the hg's fixed, but I think they would have asked for money for the car if that was the case. That invoice could be your ticket out.

You can buy the kit that tests your coolant and will show you a hg problem at napa, i think its like 50 bucks, its just some strips that change color, I'm not sure why your mechanic needs "a guy" for that.

Take it out on the highway and see what it does, if it overheats (250-260+) theres a good chance its hg's , or you wil definetly see an external leak. Just bring some coolant with you.

olsonscottm · #11 (**permalink**) 01-12-09, 02:58 PM

I bought the car on 1-10-09, and the invoice (which shows one hour shop time) is dated 12-29-08. So I think they knew, didn't disclose it, and we wouldn't have known if not for finding the incriminating evidence.

When I suggested an engine swap, I meant replacement. If you've got to pull the engine out to change head gaskets, why put an engine with 128K miles back in?

I drove for about an hour at 60-65 mph and didn't see temps above 215. Runs fine, lots of power.

I'm not sure if the mechanic wants to just run that test, or actually do a cylinder leak-down test, or some other kind of test.

I know my way around a 350, even rebuilt a couple back in high school, but this is much more complex and don't know if I should even try tackling it.

**Ranger** · #12 (**permalink**) 01-12-09, 03:34 PM

I would not replace the engine for a head gasket. Especially with a used one. Never know if that one will go. If you are going to attempt this yourself, there are several people here who have done it and have written some very good tutorials on doing it. Check the Tech Tips section. Might also want to contact 97eldocoupe (Jake). http://www.cadillacforums.com/forums...t-inserts.html (Northstar Repair without inserts)

Destroyer · #13 (**permalink**) 01-12-09, 09:22 PM

Quote:

Originally Posted by Ranger

Destroyer will guarantee you that it is a head gasket

How'd you know?

**Ranger** · #14 (**permalink**) 01-12-09, 09:30 PM

Your reputation precedes you.

buckeyemerritt · #15 (**permalink**) 01-12-09, 09:50 PM

This board is full of a lot of great information but will totally freak you out about the dreaded HG issues these cars have.

Maybe I am confused but as I have read the thread I have not seen that your car has overheated, am I wrong?

The most concerning thing in the invoice.........

I have a 96 Deville and I thought for sure it fell to the HG monster as it would overheat on the freeway when I would go over 60 mph.

I switched out the cap, thermastat, water pump, belt and tensioner and the problem has not come back, car runs at 70mph at between 196-203 now.

BTW that is one easy water pump to switch out.

Also did you buy from a dealer or private seller?

Laws are much different on what they are required to tell you.

If it is a private seller you might be out of luck as most states do not require private sellers to disclose any defects and all sales done are done "Buyer Beware"