engine and radiator flushes?

[BerniniCaCO3]

Hi!

I've been doing my own repairs over the past month, having fun with learning about cars.

My car has been running hot, so I was going to replace the radiator tomorrow. I've checked most other elements and there's nothing left but the radiator. Rather than drive 10 miles to a radiator specialist and pay $100 to learn it's clogged, I'll just replace it with a new one for $100.

But what I was wondering is, is there still a benefit to running water and a quart of corrosive coolant flush? Will that clean out scales in the engine block to improve coolant flow, as well as scales in the (soon to be replaced) radiator? If the engine block doesn't really clog like the radiator, and the purpose is really just to clean out the radiator I'm about to discard, then I won't bother.


Second question.
I'll be doing my own oil for the first time, too; it's been about 3000 miles since I bought this car and it was supposed to have just had an oil change.
They also make an engine flush; is this worth running through the engine? I have no particular reason to worry about my engine, it's running smoothly; but I'm wondering if this is a good part of general maintenance? The car's 20 yrs old with 112,000 miles.
Or, if these chemicals can also damage the engine, then perhaps I shouldn't.

Finally, just curious how often I should take off the oil pan and replace the gasket, check the seals? I'm just looking for new ways to pamper the car, and learn a few more mechanics while I'm in the mood for doing more car repairs.

[BerniniCaCO3]

Oh btw, when I replace the radiator I'm going to lose that small amount of transmission fluid that's in the radiator. How much is that, and will I want to replace it? Or is it a negligible quantity?

What kind of transmission fluid does a 1990 grand marquis use?


OH-- and just curious. Does the coolant flow in through the top and exit through the bottom hose, or flow in through the bottom and exit through the top? Someone was asking me that question yesterday, and I was embarrassed to say that I hadn't a clue!

[1987cp]

AODs use Mercon/Dextron III. Mobil-1 tranny fluid also works good, or TrickShift Synthetic. IIRC, Mercon V is considered to be compatible, and I think that's what comes in the big jugs at Advance and O'reilleys. I'd be surprised if the stock tranny fluid held even a quart. Be prepared to repair the cooler lines in case the nuts don't want to turn.

Most people say the best engine flush is to do normal oil changes and not bother with flushes or solvents. Same with transmissions. You'll want to note that one hears stories of high-mileage AODs that died immediately following a regular fluid change because the bands and junk were in poor shape and the garbage in the old fluid was helping it hang in there and not slip. If you change the transmission fluid, look into getting a bolt-in tranny drain plug. Drill one hole, and next time you don't have to lower a panfull of fluid and make a huge mess. B&M makes a plug kit that a store in your area can probably obtain, or IIRC Summit has a house-brand plug kit if you're planning an order from them.


What oil pan are you talking about removing to "check the seals"? IMO, engine oil pans aren't worth bothering about with the engine in the car unless you have a good reason for it ... the huge suspension crossmember makes it basically impossible to snake the pan out of there unless you raise the engine a few inches off the mounts.


I might have missed something from another thread, but what makes you think replacing the radiator will solve your cooling problems? I assume you've already replaced the fan clutch and verified that your thermostat is rated at not more than 195 degrees F and is opening properly?

[Tiggie]

I tend to shy away from the coolant flushes. They tend to be hard on the all important heater core (you don't want to replace that since you have to pull the whole dash).

Instead of coolant flushes, I just drain the old coolant and add water back, then drive the car. I repeat this process until the stuff that comes out is mostly clear. I've had to do anywhere between 3-10 cycles depending on the car. Drive the car in D (not OD) at highway speeds to get the rust moving around. Use hot water to refill after draining to keep the thermostat happy and make it easier to refill.

Measure how much antifreeze comes out on the first run. Usually it is about 6-8 quarts. With a total of 14 quarts in the system, adding straight antifreeze back works well since half of the system should be water by that point.

I don't use engine flushes. They usually contain a seal conditioner which is good for making your engine seals swell and pop out, causing leaks. They are also good for loosing engine crud and stopping up your oil pickup, leading to a dead engine very shortly. Use a good conventional or synthetic blend. I typically use Pennzoil. This will slowly clean your engine while protecting it.

Is your radiator really stopped up? Check the fan clutch first before replacing the radiator. It's the main cause of box overheating - especially if it overheats in traffic but is ok on the highway. I've yet to see a box with a good original fan clutch unless it's really low mileage. To check it, get the car up to normal temperature. Turn off the car and try to move the fan. It should be hard to move. If not, replace the clutch. It's an easy job. Get a thermostatically controlled one to replace it.

Is the car overheating just on the highway? Low quality lower radiator hoses can fold up and cause overheating. Check to make sure yours is firm (might have a spring inside). Check with the car cold and no pressure on the system (remove radiator cap).

If the car is overheating all the time, check some other things. The thermostat might be to blame. You can test it but it's really easier to go down to the auto parts store and buy a new one. Don't get a cheap one. Get the "better" one and don't forget the gasket. You want a 190/192/195 degree (depends on manufacturer). Be careful installing it. Make sure the thermostat stays in the housing and doesn't move or you'll crack the housing when you tighten it down.

Also is your coolant a 50/50 mix? If it's over that, the car will overheat easier. Guess it goes without saying to make sure it is full of coolant too. There is a Full Cold mark over on the overflow. Check it cold. Usually if there is some in there you are ok. Also never hurts to replace the radiator cap. A 7-psi (motorcraft RS-79) works well and doesn't stress older hoses as much as the factory 16-psi. You lose a little boilover protection but if it gets that hot you have problems anyway.

No need to take off the oil pan and check seals. Most boxes leak a little here and there. If it's not gushing, don't worry about it. Just be sure to replace the oil filter when you change the oil. 5 quarts with filter change reqardless of the dipstick reading (there were some defective dipsticks in 1988-89).

Want to do more maintenence? Replace the air and fuel filter. It could probably use plug wires if they are original or old. Spark plugs (Motorcraft coppers - don't use platinum). Check the coolant hoses to make sure they are ok (look for swelling, softness when hot with pressure on the system). The PCV valve and (and screen underneath if the car is 1986+) are always good things to replace. Look on the valve cover for pre-1986 and on the lower intake manifold right near the firewall on 1986+ (as long as it's a 5.0/302 and not a 5.8/351). Tranny fluid and filter changes aren't bad ideas either.

Oh yeah, don't forget to replace the plastic TV bushing on the throttle body with a brass one. It's on a cable that leads down to the tranny. If the bushing fails while driving, it roasts your tranny in about 20 miles.

[BerniniCaCO3]

There's not much left BUT the radiator.

I replaced the fan clutch yesterday along with the power steering, it was no big deal to do and not terribly expensive; but looking at the old one, the old one still feels good. It's not "spinning like a pinwheel," the resistance is the same as on the new one.

I replaced the thermostat last month when I did the water pump. I'm not sure I got it centered correctly when I installed it, and I ended up using regular silicone when I ran out of the official gasket sealant: so if what salvo handed me (they didn't have any choices in thermostats) is going to be a cheap one, I don't mind redoing the gasket while I'm at it.
I haven't let the car idle until it gets up to temperature and felt the hoses, but it does seem to work: on a cool night it will get up to the "M" on NORMAL and then, suddenly, fall back to between the O and R: the thermostat opening, I presume. So I believe it's working fine. But, again, I can upgrade to a higher-flow thermostat? Why not.

During the day, it just creeps up to the M, and then on to the A :-( And if I'm going uphill, or stuck in traffic for over 30 minutes, on to the L. So the thermostat functioning isn't always as clear as at night.
It's not overheating, yet, but I'm pretty uncomfortable with that. It made me nervous the entire time I drove back from Virginia with the needle going between A and L, and starting to creep up further when I was stuck in traffic.

I replaced most of the hoses, too. The upper and lower radiator hoses, the two (bypass?) hoses that come off the water pump and into the thermostat and engine block. The only ones I didn't replace were two hoses (oddly coupled in the middle, which fell apart once: why didn't they just make one hose?) that, I presume, go back to the heater core. They don't feel obviously spongy though.

I haven't done a proper flush yet. I had the lower hose fail on me about a month and a half ago, and the coolant that spilled out was rather rusty (I'd bought the car 3 months ago, so I don't know when it was last changed). The shop changed that hose, I wasn't doing my own work yet, and refilled with fresh coolant.
Then when the water pump started leaking, and I replaced that myself, I drained the coolant from the radiator once more. Seemed a bit slow: took about an hour for most of it to evacuate, and two hours until it completely stopped. Ran water in the top, it seemed to come out the bottom clear; then refilled once more.
It's been a thousand miles since then, and the fluid is still obviously, clearly green, with only wafts of rust just off of the radiator cap (which I then replaced too, just $5, in case it was losing any pressure through there...).

I understand that you can do pressurized flushes, with the corrosive cleaners, or just straight hose water, running it through the heater core? A "back flush," the guy at salvo was telling me about? To get to more of the system, rather than just a drain and refill of the radiator. Maybe worth doing.

[gadget73]

Sounds like a clogged radiator to me more than a bad thermostat. The creeping temperatures in traffic and under load are pretty typical signs of either a fan clutch or a clogged radiator. Since you've replaced the fan clutch, that doesn't leave much.

Does the connector by chance have 2 wires and 2 vacuum hoses connected to it, or is it just a coupler? If its got wires and stuff, its the thermal blower lockout for the automatic climate control system. If its just a connector, its probably where the TBL should be, or would be if the car had the auto controls. If you have the connector and automatic climate control, then someone probably deleted the TBL, probably because it went bad and they wanted the heat to work.

[BerniniCaCO3]

Just a connector! I thought it strange.
What is a TBL?

[BerniniCaCO3]

and as far as my plans for tomorrow: just drain the radiator, replace and refill? Or do I want to do more thorough flush of all the coolant, maybe under pressure (just from a water hose) or using chemicals?

Coolant was effectively replaced twice in ~1000 miles, so it's probably good. Is the flush mostly just to get all the old coolant out of there?

[gadget73]

TBL = thermal blower lockout. It keeps the fan motor from kicking on in the floor position until the engine warms up enough to actually make hot air. In reality, its a device that breaks and makes the floor position not work at all. Cars without automatic climate control do not have this.

The flush helps stir up and evict sludge from the system. The tee adapter things are like a buck, and you can just get rid of the connector and put the flush tee in there if you'd like.

[BerniniCaCO3]

Is there a reason to put the T flush adapter in there, rather than filling the radiator with water and idling the engine to get everything moving?

Hmm... I'm thinking about just adding flush to the overflow tank and driving around for a day, THEN draining everything; a problem?

[BerniniCaCO3]

I haven't actually replaced the radiator yet... going to try to get to today.

[Tiggie]

By any chance is the temperature sending unit original (on the intake, drivers side front, one wire)? It could just be that...

Sounds like you've covered all your bases anyway.

Wouldn't hurt to check the actual temperature of the coolant. You'll need a thermometer with a high range (I use a candy thermometer). When the car is warm, slowly remove the radiator cap (use a thick rag to keep from getting burned). Then check the temp. My '88 runs 200F on summer days and it gets as hot as 220 on mountain pulls in drive (on the aftermarket temp gauge), but it never gets above 205 in traffic (no air conditioning). It has a new cheapo one-row radiator.

My old '82 was fine until you turned the air on in traffic and it would boil the coolant. It had the original tow package three-row radiator.

[BerniniCaCO3]

Replaced the radiator 3 days ago, and it's running like a champ! I'll see tomorrow with the record-breaking 106F weather we're supposed to get... *ouch!*

A real thermometer would be a great addition when I get around to it, but I think mine's working yet.
Here's how it's doing now: in the evenings when it's cool enough, the engine gets up to between the R and M of N O R M A L, and then the thermostat opens, and it drops down to between the O and R and stays there.

During the day, up hills, in traffic, it would get up to the R and M and the just keep on going up, slowly!
But in the past few days it's dropped right back down, fingers crossed!

Maybe I could have flushed and saved the old radiator, but for $100 on a car I intend to keep running for a while yet, it seemed wise just to get a new one.

One challenge I ran into was that while it seemed most of the coolant system was flushing, the overflow tank must have sat for a while and there was a nice layer of coffee-colored crud on the bottom, where running coolant never really picked it up.

After 10 minutes spent figuring out that the lid didn't just pop off, but was glued; I opted to use a pressure washer, and cleaned it out nicely!

So my cooling system is now almost completely overhauled
The only thing left, pray it doesn't go, is the heater core.... btw, since the heater core is just like the radiator in construction, if the radiator was clogged, is the heater core likely to be clogged too? When you have the AC on and don't want heat, is there a heater core bypass to keep any coolant from running through it and venting thermal energy to the cabin? (even if you haven't opened the fans to blow the heat away from the heater core, as per heating in the winter, you'll still have some heat coming into the cabin...)?

[BerniniCaCO3]

Oh, in terms of radiator replacement: the only trouble I ran into, was that the transmission coolant lines did not want to thread back in. Well, the bottom one went in, but the top one just spun uselessly, the threads never beginning to catch.

I pulled out a tap and die set I'd picked up a few months ago, and had to re-thread the line to make it screw in!

I think it was 1/2"-20, but if it wasn't, it's 1/2"-20 now!

[1987cp]

You re-threaded what???