I pulled the radiator out and put new hoses on, and am still having problems with coolant loss. It seems as though the engine is burning coolant somewhere. There has been some very faint smoke coming from the back of the engine. What exactly am I in for with this thing? Does the entire engine need to be pulled and something fixed? Bad seal or gasket somewhere? Would it just be easier to throw in a crate engine? Your help is greatly appreciated....

This is all on a '89 L98.

 

One option is to pull your plugs and look for coolant spewing out when the engine is cranked over. I hope that a cracked head or gasket IS NOT the problem

 

Sort of curious what made you pull the radiator and change the hoses

There are two common reasons (and probaly a lot of others) why the L98 looses coolant and you may have touched on the major one!

Intake Manifold gaskets develop leaks at the rear of the manifold! Your car is about the right age for this to develop. Symptoms are the smell, some steam and if you get under it while it is running, if it is bad enough you will see drips

Second and third reasons...head gaskets and or freeze plugs
For head gaskets, get a compression test and or check oil for presence of coolant

For freeze plugs, do a visual under the car

Jack

 

I pulled the radiator and the hose to see if anything could be leaking from there. After checking the hoses, it seemed like a good idea to replace them while they were off. Other than that, I wanted to clean out the radiator.

There has been a slight smell of burning coolant, as well as the steam coming off. No drips have been spotted though.

It sounds like it may be the intake manifold gasket. What is required to fix this? Is it something I can do myself or should it be taken to a shop?

I'm guessing the head gaskets are ok, but I'll double check the oil. Lastly, what should I be looking for in the visual of the freeze plugs? Are you talking about the spark plugs here or something else? The plugs were changed about 6 months ago, so those should be ok.

 

Well, this past January my slow use of coolant turned into a full blown head gasket. The spark plug on the driver's side near the firewall was where all the coolant poured out. I think this is number seven and a popular source of head gasket leakage. I was told that Iron block with Aluminum heads will cause problems if the coolant was not changed as required. Well, the previous owner must have not changed the coolant on a regular basis. When I removed the head gaskets, there was a few really corroded spots on them. I hope this is not your problem... but I did the job myself and it was a good experience (it was actually fun). I got a lot of advice here that helped greatly. If this ends up being the problem, drop me an email and I'll pass some lessons learned to you.

Skip

 

If you take the intake off to do the intake gaskets, you really should do the head gaskets. They will blow between #5 and #7.
Yes, I am a victim of this 89 head gasket phenomenon
It's a big job. You should do it yourself if you can because it is labor intensive. You can totally do it. This forum WILL help you every step of the way.

 

Are there any good sites out there that give instructions on how to change these? Also, where is the best place to buy replacement gaskets and parts?

 

Radiator pressure tester. They hook up to the radiator and look like a pump. With the radiator full, pump up to around 15 pounds and see if the increased pressure forces coolant out of a hose or freeze plug or somewhere.

 

Quick, change your oil and check to see if it is brown and has a foam on it. If the antifreeze is leaking into the oil, the water component boils off and goes out the exhaust, but the glycol coats out on the bearing surfaces and denies them proper lubrication. After that...well, you don't wanna know. Good Luck!

 

I'm guessing 5 and 7 go first because they fire next to eachother and spike in temperature more than the rest of the block & heads.


I've been consuming coolant, and am getting smoke, maybe steam up through the trannytunnel into the car. I had thought it was my gear oil burning on the front ypipe, since my 4 speed is shot... but now I'm beginning to think it could be my source of coolant loss. Does seem to be whitish smoke.

I just redid that damn intake gasket 20k ago when I bought the damn car.

 

As others have posted, #7 is the most likely spot for head gasket failure on the the early aluminum head motors. Per GM's Bulletin, the problem was the composition of the gasket (and for some strange reason, the language stating that "the gasket has been redesigned to lessen the incidence of galvanic corrosion" has been removed from that Bulletin). '91 had a redesign which seems to have resolved the problem. Compression may be normal until it completely fails (mine was). If the coolant looks horrible, idle is less than perfect, heater core plugged, aux fan coming on all the time, or there is a slow loss of coolant or maybe it's boiled over on shutdown once or twice, you should suspect that the gasket is leaking. After researching what was being said back in '90 (including several lawsuits because of it), I think GM got away with a lot on this issue as the probem was apparent when many vehicles were still under warranty.

 

So, I basically need to:

1. Check the oil for coolant. If there is some in there, than it is a head gasket.

2. Pull plug #7. If there is coolant there, it is a head gasket.

3. Otherwise, just do the intake?

I'm somewhat confused here on what to take care of at this point.

 

You will not necessarily see coolant in the oil or find any in a cylinder. Look for a spark plug electrode that is different from all of the others and/or rust on the plug threads. Some radiator shops can also check the coolant for the presence of exhaust gasses, so you might call a few and see if they have that capability, but if the coolant was changed within the last 5k miles and all ready looks like crap, there is good probability that exhaust is contaminating it.

GM's redesign addressed not only the head gasket but the intake manifold gasket as well since both were prone to leakage. The '91 and current production heads are counterbored at the front and rear intake bolt holes for gasket retainers. This keeps the intake gaskets in place during installation and was successful in stopping most of the intake leaks (which are generally external - ie visible - and not internal. Also there is quite a distance between the coolant passageways and the intake ports, so an internal manifold leak doesn't generally happen unless the manifold has been eaten up by galvanic corrosion, which can be caused because exhaust gasses are getting into the coolant).

The leak could be anywhere so you need to narrow down the possibilities. If it runs well and the idle is perfect, it is probably a hose, the radiator or maybe even a bad cap or an external leak at the manifold or thermostat housing. Pumping up the system with a pressure tester should reveal an external leak and you can usually smell coolant. If the coolant is dirty and the idle is lumpy or there seems to be a slight miss, then suspect the head gasket and it's easiest to just pull the #5 and #7 plugs and compare the two. If they look ok, then check #6 and #8 as I've seen a few incidences of the head gasket failing here too.

 

Thanks for that info. The radiator and the hoses are all fine. I took them out and cleaned them out. Hoses were just put on.

I see steam coming off of the engine once it is warmed up, which is why I thought the engine was burning it off. This would lead the cause to be one of the gaskets, would it not? I'm hoping that it is just the intake manifold gasket, as the head gasket seems to be much more complicated.

 

I had a similar issue and unfortuniatly it was not the gasket it was the head. The previous owner didnt change the antifreeze often and it ate the Al head. On the up-side I pulled the head, my machine shop fixed it and did a port job, I installed a new, bigger cam, etc..... Now it's really lots of fun to drive. Im with everyone who says to pull your plugs and check them, that will be the first indication. Also do not start the motor, if you are leaking into the combustion chamber you could do serious damage if to much fluid builds up into the chamber and you turn over the motor.