Looking for some advice on a 4k that seems to be leaking coolant from a plate on the rear of the engine, facing the firewall (see photo attached). The car overheated about a month ago, which is likely the cause of the leak. Has anyone had this issue before, or can give me some suggestions on what i need to replace?

 

Any suggestions would be be greatly appreciated, thanks for you time.

From what I know, that plate is just that, a plate to stop the coolant coming out. Other engine variants have a welch plug there instead. Assuming you haven't done any damage from running hot, take of the plate and replace the gasket with sufficient sealant?

Yup, my 3k had a pipe outlet on it for the heater core lines.

The 4k I swapped into my ke30 had that blanking plate.

After swapping over the 3k cooling setup onto the 4k, I had a leak from the same place.

 

Best thing to do if the leak if from that area is to remove it, then clean up the back of the head where it bolts to with a razor blade, along with the inner side of that plating as well. Apply some good sealant and bolt it back up.

 

Should sort your problem.

Edited February 18, 201313 yr by shiryo

Jeff & Rone are right. The plate is there for moulding of the aluminium head, so they can remove the "sand" or whatever they used to fill the water jacket areas during head manufacture. On most K motors, the plate is just a blanking plate. On some K series, one of the heater water lines is connected to this plate, as Rone states. Most K series users have had this problem at some time. Unfortunately, it's in a horrible position, & requires the head to come off. Be very careful taking the plate off, as it is very easy to strip the threads in the head, if bolts are frozen. You will often find when you remove the plate that you are met with a lump of "muck" up against the back of the plate.

 

This often eats/corrodes through the plate, so the leak could well be through the centre of the plate, & not the gasket at all. If this is the case, you will have to replace the plate itself. This build up is because the water flows are not very good around the back of the head, as coolant flows in & out of the engine to the radiator through the front of the engine. Invariably the no: 4 cylinder runs hotter than all the rest, and it is not uncommon for no: 4 cylinder to be the first one to have a ring/wear or pistion problem. I've even heard of some racers using a lower heat range spark plug in no: 4 cylinder, because of this. A mod that is often carried out on race cars, is to feed the water from the rear of the head back to the radiator to assist in better water flow through the rear of the engine.

 

Cheers Banjo

Edited February 17, 201313 yr by Banjo

Thanks Jeff, Rone an Banjo for the helpful advice. It's good to know this is a common issue with these motors, I will clean it up and put it back with some sealant (the plate itself seemed in good nick) and hopefully that should solve the issue.

 

Thanks again for the useful info.

Despite Banjos words of caution, and my best efforts, the bolt heads snapped off. The head is now off. I guess I will need to get the stuck bolts taken out, but what else should I be doing/replacing before it goes back together (keep in mind it has overheated, but the head gasket looks fine)? I will be looking to get my hands on a Gregorys/Haynes manual as well.

Whip the valves out and check the condition of their seats. With the head off you should at least grind them in if they are good, or have them re-cut if they are badly worn.

 

Check the head for straight with a steel straight-edge and feeler gauges, or have a head shop do that. It may still need a skim. The head gasket set will include new valve stem seals to be fitted.

 

The car overheated about a month ago, which is likely the cause of the leak.

I assume you mean the leaking plate was the cause of the overheating. It would be unfortunate if there was some other cause of it overheating that you didn't solve this time around! Whip the radiator out and flush it upside down, that can't hurt. Was the car tending to run hot in the past?

It's a bummer when those bolts freeze & break. I've done it before, hence my warning. OK, centre pop the broken bolt very carefully, as close to the centre as you can get. Drill the bolt right down through the centre, through into the water jacket if necessary, with a sharp 3 mm drill. Keep the drill straight. Then enlarge the hole with slightly bigger drills until you almost reach the bottom of the threads of the bolt. Squirt it with WD40 & then try to get ease it out with an "easy out". If that doesn't work, then drill it our to the bottom of the bolt threads & then somtimes you can get it out with a tap. If all else fails, then there is usually enough metal in the head to go up a bolt size. One of the reasons these bolts freeze, is that the threaded holes are not always blind, and sometimes go right through into the water jacket, allowing the water to corode the bolt tip & head together. Good luck.

 

Cheers Banjo.

 

P.S. If you're down Greenbank way sometime soon, I've got a Gregory's manual in G.C. you can have for $ 10.00.

Edited February 26, 201313 yr by Banjo

@altezzaclub The original cause of overheating was that the bottom radiator hose was apparently severed by a corroded pipe that came off the rad (didn't see it myself, got a brand new rad + hoses put in while I was at work and that's what I was told). Since then, the plate has been the only place i could see coolant leaking while the engine was running, and it hasn't had issues in the past, so fingers crossed no more issues after this!

 

@banjo I will attempt this on the weekend. Regarding the Gregorys manual, I probably won't be down that way any time soon, but I'm happy to pay for postage?

 

Thanks for the invaluable information guys, ill let you know how i go with it.

PM to me your address & I'll post the Gregory's manual today.

 

Glad we could be of assistance.

 

Cheers Banjo.

I would just drop the head off at a machine shoip and get them to check it out, they will machine it flat and clean it in their acid bath!

 

Then you plonk it back on knowing that its in good condition.

That sounds like a good option if it looks like it needs to be skimmed ke70dave, any recommendations for a machine shop in Bris and what would it cost roughly?

Hi Jader,

The weekend before last, I blew a head gasket in my 4KU (no: 4 cylinder), which is in a KE30, which originally had a 3K in it. I took the head off, skimmed it, and refitted, but took the opportunity to take a photo of the head "rear cover plate", whilst it was out. It shows the plate, as fitted to some early 3Ks, where a heater pipe was attached/fitted, as described earlier in this thread.

 

Be warned that the plates on the rear of 3K, 4K, & 5K heads are not all identical. I think one of the bolt holes on a 5K plate is in a slightly different position.

 

 

 

Cheers Banjo

Edited April 24, 201313 yr by Banjo

(Same car and similar issue, so figured I would piggy back this thread)

 

Having issues with overheating again:

• Coolant seemed to be leaking from the cap of the overflow bottle
  
• Coolant seems to be getting into the oil - milky residue on oil cap, oil level is higher than before on dip stick and seems less viscous (still brown though)
  
• Also leaking a bit of oil
  
• rad and hoses < 1 year old
  

Tried the "headgasket bubble check" as mentioned in other threads - water was overflowing at a constant rate, but could not see any bubbles. When thermostat opened after ~5min there were a few big bubbles, spilled a bit of water then resumed overflowing at constant rate with no bubbles. Gregories manual suggests warped/cracked cylinder head/block - last time the head was off (< 1 year ago) it all looked good/straight.

 

Should I get the cylinders pressure tested? Could it be anything other than issue with head/block/gasket? Thanks.

• Coolant seemed to be leaking from the cap of the overflow bottle
  
• Coolant seems to be getting into the oil - milky residue on oil cap, oil level is higher than before on dip stick and seems less viscous (still brown though)
  

 

Those two certainly suggest a head gasket or a crack. Does it start OK when cold??

 

We hooked a screw-in compression gauge extension onto a compressor's air-line and pumped each cyl up to 100psi then watched for it dropping, but if you haven't got the air compressor get a garage to do a leak-down test like that.