Leaky Radiator

[1990QOwner]

The radiator on my Q has a hole in the side of it . I have tried some of the liquid radiator fix products but they haven't worked. Does anyone know of any other solution for fixing this?

[Rex]

Replacing the radiator is the only smart/long term option. Over heating an aluminum block motor is very bad.

If new is too $$$, check the classifieds section for someone parting one out.

[1990QOwner]

Thanks for the info, I think I will do just that (replace it). By the time I am done with this car it will have every part replaced on it . O well, it is a fun car and I am using it to get more familiar with auto mechanics. With the front end how it is it probably will be a big project doing it wont it?

[Rex]

It's not that big of a project, the key is to take advantage and go ahead an flush the coolant. Also, if you do not have an after market ATF cooler, it's a great time to add one.

I think there's a basic "how to" for both in the articles section.

Expect to scuff your knuckles.

[1990QOwner]

OK, do you know where I can get an aftermarket ATF cooler? And do you know if there is anything else that I will need to do or replace while I am in there?

[Rex]

Check out the Articles sectionhttp://www.nicoclub.com/subpag...l#q45

Here's the one on the radiatorhttp://www.nicoclub.com/articles.php?id=164371

Here's a thread on coolershttp://forums.nicoclub.com/zerothread?id=106293

[Jesda]

Once you remove the four screws holding the big fan in, its a breeze. Just put the front end up on jack stands to make it easier.

[1990QOwner]

Do you think that the thermostat could be bad? Would that make the radiator run out of water and not use the water in the reservoir? The radiator is clear out of water and the reservoir is clear full. Some have recommended completely taking the thermostat out for better coolant circulation, has anyone ever tried this on a Q?

[Q45tech]

The last thing one would do is remove the thermostat since the system might take 30 minutes to warm up in winter wasting significant gasoline and making a mighty cool ride to work.

Thermostats and both coolant caps should be replaced every 3-4 years at minimum.

Why not repair the system as it was designed to function instead of thinking of ways to redesign.

[maxnix]

vWhy not repair the system as it was designed to function instead of thinking of ways to redesign.

Ah, you know those Nissan guys can't design an intake, nor an exahust. Amazing the thing even runs.

[goody90q45]

Do you think that the thermostat could be bad?......Some have recommended completely taking the thermostat out for better coolant circulation, has anyone ever tried this on a Q?

Funny that you should bring this up. My Q has been warming up slowly and since the thermostat fails open I suspected it was time for replacement. It's not been an issue since last winter but with winter rolling around again it's time. I removed the thermostat housing this afternoon to discover I don't have a thermostat, and I've owned my Q for over 2 years. Oops. I put an OEM one in.

My Q spent most of its life in Las Vegas and had only been in NorCal for a couple of years before I bought it. I'm curious if removing the thermostat is a practice in hot weather cities, including southern Arizona, where you're at. I think it stays warm year-round in your part of the country.

Other than taking a long time to warm up and possibly not reaching the correct operating temp is there other issues with leaving the T-stat out (in warm weather only)?

[maxnix]

Thermostats work fine in Texas.

[1990QOwner]

Well, I would be delighted if it never did warm up, It would be better than it overheating....and besides with the heat here it is warmed up 2 min after I start it. It keeps heating up on me and I have to pull over and wait on the road for 1/2 hour for it to cool down enough to drive again.....I went through that for 2 hours today til I finally called a buddy with a truck and trailer. We discovered that the radiator was CLEAR empty and the reservoir was clear full....he figured that it was the thermostat. What is the process of taking the thermostat out? I think I will try it. I poured a bunch of the radiator fixer in and carefully followed the instructions and it seems to have fixed it . But I am quite sure that the head gasket is blown because I have been smelling the sweet flavored smoke .

[Jesda]

I also suggest backflushing your cooling system. The stopleak stuff, if you used the kind with metallic flakes, is hell on your car.

[1990QOwner]

I didn't use the kind that is the flakes. I used some liquid stuff that looks just like mud.

[goody90q45]

....he figured that it was the thermostat. What is the process of taking the thermostat out?

Pretty simple really. Remove the center engine shroud (three 10mm bolts/nut) and under it you'll see the thermostat housing. Remove the three 12mm bolts and it falls out. You'll need RTV gasket sealant to put it all back together. There is no paper gasket.

[Jesda]

I didn't use the kind that is the flakes. I used some liquid stuff that looks just like mud.

Whew!

[elwesso]

I agree with jesda.... If you would have asked me to put in that stop leak stuff, i would have said RUN AWAY. that stuff is only going to make stuff worse, like clog your heater core and make the heat transfer inside the motor worse.

Definitely when you replace your radiator, flush the entire system in hopes of getting most of the stuff out... Be sure to make sure the heater core is open.

It KILLS KILLS ME WHEN people think these sugar pill instant fix things can fix real problems with failed METAL parts.... Think about it this way, if its enough to clog a leak in your radiator, think about what else is clogging??? Every Q should have a barcode scanner that would give the owner a large electric shock if they ever tried to put in a poor product... im afraid thatd be the only way people would learn......

[1990QOwner]

The radiator fix-it stuff is a band-aid for until I can get a new one....of course I know that isn't going to fix it permanently.

[Jesda]

Its a bandaid that infects your kidneys.

[1990QOwner]

Hey, U guys take it easy on me. I'm still learning.

[StarPD]

Hey, U guys take it easy on me. I'm still learning.

Do yourself a favor.Pull the radiator and take it to a GOOD radiator shop and have it rebuilt, preferably WITHOUT an integral trans cooler. While it's in the shop, backflush the heck out of the motor to remove most of the junk you put in it.

Then when you reinstall the radiator, with a new thermostat and all new hoses of course, including heater hoses, get and install a GOOD trans cooler. This is essential if you eliminate the factory trans cooler in the radiator.

Do NOT scrimp on the radiator hoses. Use OEM or better. Be very careful to use big enough hoses and fittings for the trans cooler, and look for one with a thermostat, either integral or separate. If it was me, I'd use good high-temp, high-pressure hoses with braided stainless steel covering. More money, but better insurance against hose failure, which could lead to trans replacement. There are a number of places online that you can get good trans coolers from, B&M is one.

Since you should be doing all this, a complete trans flush is in order too, and repeat it every 24 months. Also, change diff lube and use synthetic.

Finally, since it appears to be questionable whether the motor was overheated or not, you might want to have a compression and leakdown test as well as an oil pressure test (done with a hot motor) performed by a reputable shop, preferably one that is familiar with Infinfits after replacing the radiator, but before you do anything else. You may have damaqed the motor beyond repair if it was overheated to any degree. Better to find out now than ending up being stranded somewhere with a seized motor. You may want to wait until you have the new radiator back in the car before you spend all the extra money on the additional thinhgs I suggested. If the motor is toast, replace it or get rid of the car. If it's okay, THEN do the rest of what I suggested, but do NOT wait long, and do not drive the car much at all until you do these things. If you drive without a trans cooler at all, you may overheat the trans and kill it.

Good luck.Let us know how you make out.

[qship96]

Why try to rebuild an old rotton radiator when you can replace with brand new for a few hundred bucks?

[StarPD]

Why try to rebuild an old rotton radiator when you can replace with brand new for a few hundred bucks?

Rebuilt radiator should have a complete new core. Unless the rest is corroded, nothing more is needed. Besides, eliminating the integral trans cooler (replacing it with a GOOD aftermarket one of course) provides considerably more and better engine cooling. A good radiator shop can put almost any size and thickness core that will allow the radiator to fit in its original mounting, providing even better cooling. A new radiator should not be necessary, but will cost a lot more.

YMMV.

[1990QOwner]

It looks like B&M has a bunch of different models of ATF coolers. Which one would you recommend?

[StarPD]

It looks like B&M has a bunch of different models of ATF coolers. Which one would you recommend?

Depends on what your transmission is worth, and what your location and driving habits are. I've always found that when I try to save money, I always screw myself. So I'd get one of the larger capacity ones, and use a thermostat and separate bypassable high-flow trans filter with a replaceable element. I'd also use aircrat grade high temp, high-pressure braided stainless covered large hoses and reusable non-skive fittings. Expensive, but a lot cheaper than a new trans.

The B&M 70297 looks pretty good though, as it has its own thermostatically controlled cooling fan. Others may be bigger and have more capacity, so maybe checking with guys who have pickups that pull heavy trailers in the mountains might have more insight. I think for regular cars, like the Q, the 70297 would be more than adequate. B&M does have a thermostatic control valve to ensure that trans oil temp reaches operating temps quickly, then makes sure that the cooler keeps trans oil temps from getting too high. The fan on the 70297 then makes sure that enough air is passing through the cooler when the vehicle isn't moving fast enough to ram enough air through it to allow it to do its job. This is common in heavy stop and go city traffic and and even on some steep mountain grades. A good replaceable element bypass type filter located before the cooler will ensure that any wear particles don't go into the cooler and/or back to the trans. Not sure if there are location problems for a 70297 in a Q, might be best to scope it out before investing. If there's no good place to put it, there are others that would suffice. Anything is better than nothing, and probably better than the factory integral one in the radiator.

[1990QOwner]

OK, about 1/2 of that went over my head but I will ask questions as I get going. It may be a week or 2 before I start just to get all my stuff together.

My Driving habits aren't the best and I live in a hot area so I think I will go with the best here. I saw on a different thread where someone had pics of mounting a Aux. ATF cooler. I guess I can check that thread out. I also need to do some research and see where the closest radiator rebuilder place is.

[StarPD]

OK, about 1/2 of that went over my head but I will ask questions as I get going. It may be a week or 2 before I start just to get all my stuff together.

My Driving habits aren't the best and I live in a hot area so I think I will go with the best here. I saw on a different thread where someone had pics of mounting a Aux. ATF cooler. I guess I can check that thread out. I also need to do some research and see where the closest radiator rebuilder place is.

Do research it, then do what you think is best for your Q, and yourself.

[1990QOwner]

How big of a pain is it to replace the head gasket? If I did that than it would at least be able to run for a while without ruining it anymore.

[DrewQ45]

If you can see where the leak is coming from.... I have found JB Weld to be of excellent use in past vehicles. You'll just have to make sure the area is dry and rough it up with sandpaper. Temporary solution mind you.