03 Golf Coolant loss, Overheat, Oil in Coolant

Good morning from a Newbie. While waiting for my account to become active, I have been reading lots of posts about my problem, so, I know that there have been discussions about my issue, but I would like some confirmation. The problem is likely either a blown head gasket, warped head, or busted oil cooler. To start with, my car is an 03 Golf, TDI 1.9 automatic. This is my son's car and he is 17. I regularly tell him to watch the gauges, and we have dealt with coolant loss, so this is not a new issue for us. The old coolant loss issue was a cracked flange on the drivers side of the engine. When that was happening, my son allowed the engine to overheat while coming home one night.

Fast forward to now. Last Friday, he was driving and saw the Low Coolant light come on. The temp went way over 190, and at some point, he stopped at a gas station and filled up the coolant bottle. Remember I said he is 17 ? Hard to get detailed info from a teenager. When he got home, I looked for the coolant leak and could not find one. The reservoir was empty. I filled it, and after driving a bit, the light came on again and the reservoir was close to empty. Let it sit overnight. In the morning, I looked in the reservoir and there were black spots in the little bit of coolant left. I poured some more coolant in, and the whole thing became an oily soup. Obviously motor oil in the coolant. Pulled the dipstick and the oil was black, not milky. Started the engine and it sounds normal and seems to run fine. I only ran it for about a minute. Having never done a head gasket before, I decided to close the hood and do my research before messing with anything. What I learned on this forum is that the oil cooler could be one of the problems. However, would the oil cooler cause coolant 'loss'?

So, here are my questions: Could it be the oil cooler or is it definitely the head gasket? What are the best tests to determine whether it is the oil cooler or the head gasket before taking the head off? Thanks.

Black spots in the coolant is probably soot from the blown head gasket. Once he overheated it, the head probably warped and is no longer sealing. At this point STOP driving the car and drain the coolant so none can leak into the combustion chamber.

At the minimum you are looking at a head rebuild with a resurface + a timing belt kit and head gasket. The overheating might have caused other damage but you won't know until the head is off.

I would do the the oil cooler before anything. Pretty cheap and super easy to change. idparts has them or ebay.

If anything you can remove it and test it for leaks. Takes less than 10 minutes to remove

Agree with turbocharged798. Don't keep driving. Most likely head gasket and/or oil cooler since there is no external "leak".
One question. Is this a manual tranny or an automatic?? I had bought a project Jetta (1.8T this time, but still applies) that had coolant loss and "engine oil" in coolant. Oil cooler was replaced, still losing coolant and "oily" coolant. Auto tranny cooler was defective and you can't imagine the condition of the tranny fluid.

If the Al head is warped, would that not cause an external leak as well? Had that happen on a Chrysler I owned that overheated.

Seems like compression would also be going somewhere if the head was warped

Thanks guys. For the record, after discovering the oil in coolant yesterday, I ran the engine for about a minute and it ran like normal. I won't run it again till it's fixed. If it is the oil cooler, would that consume coolant? Is there a definitive way to test whether or not it is a head gasket? I've seen on YouTube a Combustion Gas Tester. It has two tubes, a squeeze bulb, and blue liquid. About $50.00 for the kit. Fill liquid to the lines, put on top of coolant reservoir, start engine, and squeeze the bulb. If there are combustion gasses in the cooling system, they will turn the liquid yellow. Then you know you have a blown head gasket. Is this a good way to test? Also, what if I take the oil cooler off, test it, and discover it is defective? Does that generally eliminate the head gasket?

I wonder if that tester works the same for gas engines and diesels-combustion gasses detected might be different??
Faulty oil cooler may/may not consume coolant. Oil pressure is higher than coolant pressure. Seems like it would mostly put oil in the coolant. May have to get some more advice on that one. But should be fairly easy to test the cooler. Didn't take much to determine my 09A tranny cooler was leaking.
Seems as though a compression test would detect a bad head gasket as HW suggested. Not unheard of for a head/gasket to fail when overheated. Just saying...

BatCobra said:

Thanks guys. For the record, after discovering the oil in coolant yesterday, I ran the engine for about a minute and it ran like normal. I won't run it again till it's fixed. If it is the oil cooler, would that consume coolant? Is there a definitive way to test whether or not it is a head gasket? I've seen on YouTube a Combustion Gas Tester. It has two tubes, a squeeze bulb, and blue liquid. About $50.00 for the kit. Fill liquid to the lines, put on top of coolant reservoir, start engine, and squeeze the bulb. If there are combustion gasses in the cooling system, they will turn the liquid yellow. Then you know you have a blown head gasket. Is this a good way to test? Also, what if I take the oil cooler off, test it, and discover it is defective? Does that generally eliminate the head gasket?

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I take no responsibility for this suggestion, but...

You might be able to rule in or out the oil cooler by bypassing it? Of course, whatever you do you do NOT want to run the engine hard or long. I'm thinking that if this thing is really losing coolant as fast as it sounds then you should be able to get a good idea pretty quickly. I'm just wondering whether you should look to replace your oil and filter first. That's going to be at least $30 - $35. Although the test for the combustion gases (assuming it works for diesels) costs more perhaps it's better because you don't have to hassle with draining oil and such; HOWEVER, I'd make sure that your crank case fluid levels aren't too high lest that cause problems; here, then, is where I would be a little hesitant to run an engine with coolant in the oil (could hurt bearings and such- um, might be too late already?).

The coolant testers work really well to pin point head gasket problems (get one made for desiel engines). Also when the car was running and using coolant was there white smoke coming from the exhaust ? If it was burning coolant that fast there would be a good amount of white smoke. Replace the oil cooler first as its easiest and test with the coolant tester before removing the head. Do the easy stuff first!!!!!!!!!

I have read that logging injector balance with VCDS will give you an idea of compression health. It would be intesesting to see a log of the four cylinder readings injector balance.

One classic, simple head gasket test is this:

Engine cold.
Cap on coolant bottle screwed on tight.
Start engine, run for 1-2 minutes.
Check coolant system for signs of pressurization - hoses feel firm, a "whoosh" when you unscrew the coolant bottle cap.

If the system is pressurizing that fast, that's a sure sign the head gasket is letting combustion gases into the coolant system.
If the system isn't pressurized, that does not mean the head gasket hasn't failed - just that it's not letting gases into the coolant when cold.

I really appreciate the suggestions of testing the oil cooler first. I will try that this weekend. I saw a YouTube video of the procedure. I'm also going to buy a Bentley manual for the car. Saw it on Amazon for $85. I'm pretty handy mechanically, so I think I could take on this project. Today, I stopped by a local VW/Porsche/Audi repair shop. They have a good reputation. Told the guy my situation. He said "Head Gasket". Especially because of the couple of times it overheated. Asked him for a price to fix it, along with doing the timing belt/water pump (since it's open already). He said 10 hours labor at $120/hour. About $800 in parts and machine shop for the warped head. With tax and all, $2300. I paid $2800 for the car. Not too thrilled about paying close to that to fix it. Therefore, I will tackle it myself. With the Bentley manual, You Tube videos, This Forum and all you guys, I should be able to make it happen.

Head gasket or cracked head.

The thing is you need to figure out if the coolant has oil or soot in it. If its oil then its most likely oil cooler, and if its soot then most likely head gasket.

Sounds similar to something that happened to my truck earlier this year - it would puke its coolant (reservoir pressurized, no recovery bottle), then at idle "burp" the exhaust bubble in the water jacket and trip the low coolant light. I suspected (and mechanic agreed) that it was the EGR cooler - not verified, since this would have been an expensive repair and this started happening after I had ordered the new engine. As a temporary fix, I put in a 10 litre windshield washer jug (fit the available space perfectly) as a recovery bottle.

If the black in your coolant is soot, and the system is pressurizing, the EGR cooler would be another thing to check. Also, there must be a dump hose somewhere to deal with cases of "WAY TOO MUCH coolant" - try jury-rigging a paper cup to catch what comes out. If it fills, then you've identified where the coolant is going (without something to catch it, it'll wind up on the road with no trace of where it went).

RacerTodd, great suggestion. Just a little scared of running the engine at all right now. turbocharged798, very true. This morning, I opened the reservoir and stuck my finger in the soup. What I pulled out was golden oil with small black spots throughout. Smelled like motor oil. I'm thinking it is an oil cooler and a head gasket. I will tear into it first thing in the morning. May have some answers then. Some of you say 'Don't Start it!', and others suggest run it for a minute to test it. Any real concern if I run it for 1 to 2 minutes to see if there is pressure build up in the coolant bottle and look for white smoke at the tail pipe.?

oil cooler test: remove both the coolant lines, tie em together and start the engine....a bad cooler will ooze oil from the coolant nipples....good luck!

jimbote said:

oil cooler test: remove both the coolant lines, tie em together and start the engine....a bad cooler will ooze oil from the coolant nipples....good luck!

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thanks....learned something new....don't know why I never thought of that before!

Sorry that I've been away from this post. Been working on the car. Follow up: I got the head off and took it to a great machine shop. The Head Depot in Fort Lauderdale. He showed me the slight gap along the straight edge. They did a great job of machining the head and fixing up the valves. Put in a new cam oil seal too. Total was $350. I got all the parts back together and then changed the timing belt. Pretty easy job with a Bentley manual and You Tube. The whole job cost me $950 (head shop, gaskets timing belt kit, etc). The local VW shop (not the dealer) wanted $2400. Pretty proud of myself right about now. The car started right up and runs great. still flushing the coolant to get the oil out of it. Getting more clear with each flush. Thanks for all the support. You guys make DIY a pleasure.