A few diff issues..mainly Overheating Engine

Hello all....been having issues with my Riv for a while now, but haven't been able to figure it out. OK, my 95 Riv SC overheats after about a days worth of driving after i fill radiator with coolant/water 50/50 mixture. When I pour coolant mix into reservoir on driver's side I don't think it goes into the radiator. So, I've been pouring directly into the rad. I also have noticed that, coolant mix boils in the reservoir. I've never seen this before so I don't know where to look next. Back to radiator, I don't know where it's leaking from but I have occasionally seen wet spots under my car tho. Now I live in apts so I haven't gotten under the Riv yet, but I kinda want to know what I should be looking for. Also, I changed the thermostat in Jan, hoping that was the problem I was having. But of course, it didn't correct my issue. That coolant is getting so damn expensive to keep buying every week , so I'd like to finally get this problem figured out. I tried going through past posts for similar situation but haven't found one yet. Any help would be greatly appreciated.

The good thing about our radiators is they cool really well, and they last a pretty long time. The bad thing about them, part of the unit is made of plastic, and when it cracks, the coolant will leak out, slowly at first. If you see the puddle on the driver side, check the top corner for evidence of a leak. Also check the upper radiator hose. If it's coming from the passenger side, check the lower radiator hose, and also if your belts are wet it could be the water pump.

When you lose coolant, the ability to cool the engine is diminished. Usually the problem only gets worse, so fix this while you can. Maybe you'll luck out and only need to replace a hose. Until then, keep a gallon of 50/50 at the ready, in case the situation gets out of hand. And don't drive the car if it's overheated!

I think I have som e insights you can use.

Around same mileage as yours I was losing coolant in my Riv. Turned out to be a couple things.

One was a very high pressure leak due to a cracked plastic radiator tank. It only leaked when you ran the car real hard. I fixed it with a new radiator. The point however is that the cooling system's engineered for ~150 K miles trouble free I was told - it is no surprise that trouble starts later.

How I found the leak -- well, it took about a year. My mechanic at the time (Doug) put fluorescent dye in the system and I used a black light to find the leak. It took almost a year from when he put the dye in to when I found the evidence. Probably because the coolant was only coming out under very high pressure and due to the way the tank was cracked, whizzing directly onto the ground.

I fixed the cooling system 6/2011 with new radiator, new heater and coolant hoses, and new thermostat at ~224,000 miles.

A few weeks ago I noticed the car was w\running warm. It was not overheating but getting close. Wouldn't you know, it was the radiator cap. Found it only because I did not have time to mess with it and another mechanic (Aaron) pressure tested teh system. The system was in perfect shape, held the presure test a long time. Aaron was stumped. I told him to replace the thermostat anyway -- when he refilled the system he noticed coolant coming out past the radiator cap. Turned out the cap was bad, not holding pressure.

Point of this is that it is likely time for you to overhaul your cooling system and you might should replace the rad cap.

You can have the system pressure tested to find any leaks, just be aware that the rad leak may not show up unless the coolant is fully hot. And if you are doing system overhaul as preventive maintenance be sure to replace the cap.

Thanks for the replies fellas...I will try to find out what side the leak is coming from and also look into replacing the radiator. I bout a new radiator cap a few weeks ago but it doesn't fit right because it has two parts that stick out (don't know a better way to describe, sorry) for you to be able to grip cap, i guess, but it doesn't allow the cap to close tightly. I got it from Auto Zone and they said it was the right one for the Riv, but I do know I need to get a proper fitting one. I am now over 200K and to best of my knowledge, radiator hasn't been serviced or replaced, so I'll add that to my to do list. Thanks again I'll keep you guys updated when I get it done. Then I'll ask more qwestions about other issues my poor Riv is having...lol

Also, any suggestions on where to get a good replacement radiator?

GMpartsdirect or RockAuto.com should stock them at decent prices. A good price for OE radiator is $180-200 + shipping.

k, thanks

R1V13RA wrote:

Also, any suggestions on where to get a good replacement radiator?

Test your radiator before replacing. Odds are there is an issue BUT 200 is 200 and it might not be the issue so why spend 200 before you really know?

I bought my rad from rockauto.com; I bought the VIstaPro. It has more cooling capacity than the OE because the tubes are a millimeter or so closer together so there are a total of 5 or 6 more of them across the radiator.

As for the cap, consider getting one from a GM dealer, they are not *that* expensive.

Albertj

Thanks for your input albertj, but how exactly do I test it? Sorry if that's a dumb qwestion, but I'm not as mechanically savvy as I'd like to be....coming soon though because I start diesel mechanic class tomorrow

R1V13RA wrote:

Thanks for your input albertj, but how exactly do I test it? Sorry if that's a dumb question, but I'm not as mechanically savvy as I'd like to be....coming soon though because I start diesel mechanic class tomorrow

No worries, it's a fair question.

Most certified mechanics have a gadget that they put on your radiator fill opening, that has a Schraeder valve on it. They can "inflate" the radiator to some amount of air pressure then, and check for leaks, and see if it holds pressure. If the pressure leaks down odds are if there is an external leak it will hiss and spit. If there is an internal leak the pressure will go down. Here is a tester ---> http://www.harborfreight.com/radiator-pressure-tester-kit-65053.html

Specifically (from http://www.cdxetextbook.com/engines/cool/coolingSystem/coolingpressure.html)
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Inspect cooling system visually
Before pressure testing the system, visually inspect the system for any obvious signs of leaks or wear in the radiator core, radiator tanks, coolant and heater hoses, water pump, all accessible engine core plugs,
cooling fan, drive belt and radiator cap and seals.

Check the operating instructions of the tester
Refer to the pressure tester’s manual for correct operation. The outside of the radiator cap should be marked with its operating pressure. When this pressure is reached, the pressure relief valve in the cap will allow a discharge into the overflow system.

Test the radiator cap
Refer to the workshop manual or vehicle owner’s manual to check that the pressure cap fitted has the correct pressure rating for that cooling system. Attach the radiator cap to the tester with an adaptor and pump up the pressure on the radiator cap spring. The pressure should hold just below the relief pressure setting. If the pressure will not hold or it cannot reach this pressure, then replace it with a new cap of the correct type and recommendation.

Test the cooling system
Before testing the integrity of the cooling system, top up the coolant level. Attach the cooling system tester to the radiator cap locator. Pump up the system pressure to slightly above the pressure recommended by the rating specified on the pressure relief cap.
Observe the pressure reading. If it remains steady and does not drop then the system is not leaking. However, if the pressure drops, look for the leak. If there is no visible external leak, then the leak is most probably internal.
If there are any visible leaks, or the pressure drops, [time for more troubleshooting as appropriate]...
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There are several pictures at the link showing the apparatus. You can also check for leaks by putting some dye in the system, you should be able to get dye at a local Car Quest or NAPA or other full-line auto parts store.

Ok...update. I was pouring water into radiator while a little warm (not cold water of course) and noticed a hissing sound and found where the leak was coming from. The bypass hose from engine to water pump had been spweing everything out. I guess I never noticed the leak because I usually ffilled radiator in the morning when engine was cold. Thanks for all the input guys

R1V13RA wrote:

Ok...update. I was pouring water into radiator while a little warm (not cold water of course) and noticed a hissing sound and found where the leak was coming from. The bypass hose from engine to water pump had been spweing everything out. I guess I never noticed the leak because I usually ffilled radiator in the morning when engine was cold. Thanks for all the input guys

OK so you probably got it on step 1 of the "textbook" solution. Sounds good. But given your mileage maybe you ought to consider replacing all the soft hoses. They are not too much $$ and Gates Rubber (the OE) has no idea if they last longer than 250,000 miles/so-so-many years anyway.