1994, C280: Testing Radiator to find if clogged

[Arv]

Hi All:

Recenlty I had a leak in the cooling system so I used Bar's Heavy Duty Stop Leak in the cooling system and it has caused big problems. The coolent has stopped circulating in the system and on very hot days, the car rapidly overheats. After putting this stop leak, the same day when I got back home after a 50 mile drive, the heater hose blew up on me. I checked the coolent tank and it was full. So I concluded that the stop leak might have caused a clog somewhere in the system, so the system couldn't suck in the coolent from the tank and the hose blew up and may be the hose blowing up cleared up the clog. So I changed the hose, test drove the car 50 miles and it seemed fine except the the temp guage will go up and down bet 90 to 110 or so on and off. Before this 50 mile drive, I had taken a short drive through the town, and the temp held steady about 90.

Then last Friday, I was coming back home from a small run about 5 miles on a hot day, the car started overheating to about 120 right as I was reaching home. I stopped and I heard some hissing sound, opened the hood and coolent spray was coming from the side of radiator where the plastic ends are. Seems like it blew up my radiator. The leak I saw was coming from right under the upper radiator hose area on the driver side at the joint of the plastic end and the radiator core.

Yesterday, I was doing some investigating and I saw the coolent spray again, but also once I saw big continuous drip of engine oil coming I belive somewhere from above the alternator.

Does this mean my head gasket is blown up also?

Is there any way I can test this radiator by removing and pumping water in the upper hose coming thermostat housing and removing the lower hose to see if it is clogged? Which lower hose shall I remove, the one right below this hose or the one going to the coolent bottle?

I wish I had not used this Bar's HEAVY DUTY Stop Leak and instead just used their regular stuff which I have used before long time ago. It has caused nothing but big headaches for last 2 weeks.

Help is very much appreciated.

Thank you all,
Arv.

 

[Arv]

Sorry, just want to correct the error in the following question,

Is there any way I can test this radiator by removing and pumping water in the upper hose coming thermostat housing and removing the lower hose below it to see if it is clogged? This big long molded lower hose (right below the upper hose) feeds back into the water pump, is it?

Thank you all,
Arv.

 

[Dave Brooker]

Sorry, just want to correct the error in the following question,

Is there any way I can test this radiator by removing and pumping water in the upper hose coming thermostat housing and removing the lower hose below it to see if it is clogged? This big long molded lower hose (right below the upper hose) feeds back into the water pump, is it?

Thank you all,
Arv.

It's safe to say your radiator's had it.

C280 rads are prone to blockage due to their design.

You can feel if a radiator is blocked by putting your hand on it and seeing if its warm all over, or if it has hot spots indicating a blockage, usually around the inlet area.

 

[Arv]

Thank you for your reply Dave. Just took a short drive and the radiator feels hot all around. So the blockage is probably near inlet area from the coolent bottle. How to unclog it? Shall I use flush.

Thank you again,
Arv.

 

[television]

If it has been leaking it will leak again when the pressure builds up. Bars leak can block water lines if it is not stirred well and poured in slowly. As it stands now it ios hard to say what is going on. Where was the original leak

 

[Arv]

Hi Malcolm:

Thank you for your reply. 2 weeks ago while coming back on hwy, I got the coolent light on.
Quite A while ago, I had a coolent leak from the head gasket, and the mechanic I used to go that time had used a sealent that time. Since then on/off, it pop's up its head. So when I get a small leak, I have been putting in Bar's Stop Leak, the regular kind with saw dust kinda particles in it. But this time I happened to see a new one which said Heavy Duty. I asked the guy on the counter about it and he said its better. So I figured I will use it, so I did. It's completely black in color. So when you shake it, you don't see anything. I shook well the bottle and put it in. This stuff has about wheat grain sized pallets in it or may be little bigger in size which end up lugging together. And it caused me a whole lot of problems.

Well did further testing. I took off the hose to the radiator from the coolent bottle and the coolent came out gushing from the radiator and the hose.

1. Does this mean there is no clog at the intake side of coolent?

2. What could be cause of oil drip? Head gasket or camshft cover gasket? It's kinda hard to see where it is coming from but it drips right on the anti-roll bar on the alternator side.

Thank you again for your help,
Arv.

 

[wireman]

You will need a new radiator.
Here's my explanation why.
There are dozens of horizontal tubes about 1.2 x 7mm bore in your radiator, it is virtualy immposible to unblock them with any kind of flushing since those tubes which are not blocked will divert any flushing medium away from where its wanted and hence there will be insufficient pressure across any blockages to dislodge them. This is also applicable to your heater matrix.

Removal of the header tanks will/might allow a rod to be used as a cleaner but the plastic tanks on modern radiators cannot be removed with leak free replacement a certainty, some heater matices have brass tanks and these can be cut open and resoldered, but again irrepairable plastics are making their way in here too.

Flush out the cooling system with a two part flushing kit (follow the instructions carefully) before you put the car back in service, get as much of the gunge you installed out of the system as possible.

Barrs leaks is not an engineered solution, like all other sealing additives its a bodge.

I suspect that your thermostat could be at the root of your troubles, it not only closes of the rad when below 80ish but also opens a bypass circuit when cold so that coolant can still circulate in the engine and heater. If its stuck partialy closed or is not opening much the 5 mile and over heat sounds very likely, however the symptoms you describe could also point to the head gasket (if you fill the coolant to the brim and run the engine from cold with the cap off no bubbles should eminate from the header tank unless the chg is duff).

It should not be possible that the cooling system pressure could rise so high as to "blow up" the rad or hoses, any hose which grows whilst under the normal pressure caps limit (about 1 bar) must be replaced since its going to the big puddle in the sky and will take your engine with it if it lets go completely.

Pressure caps can fail in a stuck open or closed position if not replaced now and again, the rubber washer on their end grows and sticks in the tanks filler neck making it a bit funny/sticky to remove the cap once its been turned to the release position and jamming it in the closed position.

Put a new pressure cap on along with stat, rad and antifreeze, then hope its not the CHG and that barrs has not taken up residence in your heater or its duo valve.

Wash away all oil deposits from your engine and observe it to find your oil leak, a sprinkle of talc will indicate an oily surface long before you can see blobs of oil on it.

Has this vehicle seen regular coolant changes? its supposed to be done every 2 years, cooling problems seem to occur on vehicles which are neglected in this respect.

 

[kth286]

Is it the straight six engine ?

If so, oil should be no higher than HALF WAY between min and max on dispstick when car on level ground.

Also is your radiator fan working and coming into play at those high temps.

 

[pomm001]

Sorry, just want to correct the error in the following question,

Is there any way I can test this radiator by removing and pumping water in the upper hose coming thermostat housing and removing the lower hose below it to see if it is clogged? This big long molded lower hose (right below the upper hose) feeds back into the water pump, is it?

Thank you all,
Arv.

just take it to any garage and ask them to pressure test the cooling system , will take 5 minutes, then just look where the coolant is coming out .
As suggested it sound pretty much like you will need a new rad, adding leak stoppers again and again will promote blockages .
The pressure tester can alos check the rad cap value as well.
Make sure some clever dick hasnt chucked the thermostat away, if its been hot a few times, replace the stat with a new one, considering the age of the vehicle take a good look at the hoses, make sure they have not gone hard .
best of luck

 

[Arv]

Hi all:

Thank you for all your help. To answer some of the questions you have asked, I had changed the coolent in Apr 07 and the car does have an inline 6 engine.

Where is the PCV valve located on this car? Cleaning it might help reduce the engine oil leak problem because pressure might build up it is clogged.

Will a Cooling System Power Flush help clear the clog in the cooling system? Any ideas?

Thank you again for all the help,
Arv.

 

[television]

Arv,,you will have to get a new rad as all of the other guy say,,they are not that expensive from GSF and Euro

 

[Arv]

Hi All:

Does anyone know the answers to questions in my previous post?

Yes Malcolm, thank you, that's where I am going to start by changing the radiator first and making sure that the cooling system is working properly like it is supposed to and then work on the oil leak I am getting. Meanwhile I am researching the oil leak prob also.

Also, if the head gasket is blown, do you ALWAYS get coolent in the engine oil or white smoke from tail pipe? Please note the word ALWAYS.

Thanks again,
Arv.

 

[Alex Crow]

your oil leak is most likely to be from the oil feed to the head in the head gasket. this is associated with the overheating you have had. as others have said, get a new rad and thermostat but flush out the coolant and fix the headgasket first. with the head gasket failure (failure of oil feed sealing, not necessarliy failure of combustive sealing, but this is a concern) oil often gets into the coolant which emulsifies in the cooling system and can eventually stop coolant circulation altogether. do you have emulsified oil and water in the header tank yet? note the use of the word yet also check the head for warpage when removed. we would probably advise around £1200 for all this work, assuming your viscous fan was working correctly but if temp is steady in traffic this suggests the fan is ok.

coolant does not ALWAYS get in the engine oil with these scenarios.

 

[kth286]

your oil leak is most likely to be from the oil feed to the head in the head gasket. this is associated with the overheating you have had. as others have said, get a new rad and thermostat but flush out the coolant and fix the headgasket first. with the head gasket failure (failure of oil feed sealing, not necessarliy failure of combustive sealing, but this is a concern) oil often gets into the coolant which emulsifies in the cooling system and can eventually stop coolant circulation altogether. do you have emulsified oil and water in the header tank yet? note the use of the word yet also check the head for warpage when removed. we would probably advise around £1200 for all this work, assuming your viscous fan was working correctly but if temp is steady in traffic this suggests the fan is ok.

coolant does not ALWAYS get in the engine oil with these scenarios.

I would say it is more often the case that oil gets into the coolant.

It is a higher pressure.

merc do a special cleaning product to get oil out of the cooling system.

oil will make the coolant hoses soft and will blow.

 

[Alex Crow]

I would say it is more often the case that oil gets into the coolant.

It is a higher pressure.

merc do a special cleaning product to get oil out of the cooling system.

oil will make the coolant hoses soft and will blow.

i agree wholly with all you say, david. rarely do we see water in the sump, sadly more often we see hoses swollen and mayonaise in all the cooling system and heater matrix. i hope i did not give any impression to the contrary, but the poster asked did water ALWAYS get into oil, i said no.

 

[kth286]

i agree wholly with all you say, david. rarely do we see water in the sump, sadly more often we see hoses swollen and mayonaise in all the cooling system and heater matrix. i hope i did not give any impression to the contrary, but the poster asked did water ALWAYS get into oil, i said no.

Fair point.

 

[Arv]

Hi Malcolm, Alexander and everyone,

Thank you all again. I see some yellow gunk the the coolent tank bottle but I am not sure if it is emulsified oil or stuff from the stop leak I put in. Is there any way I can test if it is emulsified oil in the coolent?

This is the approach I am thinking of taking for this mess. Please correct me if I am wrong.

I am going to start with radiator. Once the radiator is fixed, I will take few small test runs to make sure that there is no clog in the cooling system and it is working as expected. Once I am convinced of this, I will move to fixing the head gasket. One positive of doing this will be I will get fresh coolent/water mix in the system and I would have gotten rid of all the stop leak residues. So, if I see something in the coolent tank like Alexander says, it will be most likely the oil getting in the coolent, right? This way, I will also get a better idea how much really is the oil leak once the cooling system starts working properly (because I might see a bigger oil leak since the engine is running hotter right now beause of clogged cooling system)

Are there any things I should be aware of/precautions I should take while doing the radiator job? Any comment/opinions appreciated.

Thank you all again,
Arv.

 

[Arv]

Hi All:

Few more questions about radiator. I am looking at 2 radiators as follows both apparantly for 1994, C280.

Nissens Radiator
1994 Mercedes Benz C280 Base 6 Cyl 2.8L
NISSENS RADIATOR, 1-ROW -- 24.12 in. x 16.5 in. x 1.25 in. core size, 1.5 in. inlet size, 1.5 in. outlet size, 2-5/8 in. x 18-5/8 in. top header, 2-5/8 in. x 18-5/8 in. bottom header; Plastic tanks, aluminum core; With transmission oil cooler; Manufactured to the highest OEM standards; Pressure-tested before leaving production; Assures long service life, high cooling capacity, and high resistance to pressure, corrosion, and blows; Made of the best raw materials and constructed with superefficient fins; With Nissens' limited 18-month warranty.

The 2nd one is

Core Size: 24-1/4 X 16-11/16 X 1-5/8
Inlet Header: 17-3/4 X 2-1/16
Outlet Header: 17-3/4 X 2-1/16
Inlet Connection: TOP 1-3/8 LEFT
Outlet Connection: BOTTOM 1-3/8 LEFT
Transmission Oil Cooler: YES
Engine Oil Cooler: NONE
Mounting:
Notes: ONE ROW, PLASTIC TANKS & ALUMINUM CORE

Can someone please explain me about the sizes such as the inlet header, outlet header. top header, bottom header.

Do I need to worry about these? Which one is the right one?

Thank you all again,
Arv.

 

[kth286]

I would be approaching this as follows if you do not want to buy the Merc rad from dealer:

1. get the correct Merc part number for your car using the full VIN (someone on here can help if you are unfamiliar with process)

2. then go to a supplier that has the proper Merc number on their database for comparison with the aftermarket unit.

3.German & swedish seems to be experts at crossmatching genuine parts with aftermarket parts.

 

[Arv]

Hi David:

Thank you. The part number is on the radiator 202 500 41 03. I was just curious to know
what all those sizes meant. If you know them, please let me know.

Thank you again,
Arv.